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TROPICAL ISLAND RECOVERY Cousine Island, Seychelles Tropical islands around the world are losing much of...
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CONTENTS
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TROPICAL ISLAND RECOVERY Cousine Island, Seychelles Tropical islands around the world are losing much of their biodiversity. Cousine Island, Seychelles, is a remarkable example of recovery which runs counter-current to this trend of tropical island impoverishment. From a highly degraded island in the 1960s, Cousine Island is now a revitalized carpet of indigenous vegetation and a haven for nesting seabirds. All alien vertebrates have been eradicated, as have most of the invasive alien plants. Poaching of nesting marine turtles and shearwaters has stopped, leading to an increase in breeding numbers. The Sooty tern has returned to the island to breed after an absence of 30 years. The coastal plain has been extensively restored with indigenous shrubs and trees, bringing back the historic forest. Rats, mice and crazy ants, as well as other alien organisms, are kept off the island by strict quarantine measures. Three threatened Seychelles endemic land birds (Seychelles warbler, Seychelles magpie robin and Seychelles white-eye) have been established and are breeding successfully. Overall, the Cousine Island restoration programme has improved the compositional, structural and functional biodiversity of the island, and is sustainable in the long term. The coral reefs are also recovering after the mass coral bleaching event at the end of the last century. Cousine Island is thus paving the way in the craft and science of tropical island restoration as a legacy for future generations. This book is about the recovery of Cousine Island and its natural history, told in detail and with profuse illustration. It for restoration ecologists, tropical ecologists, island enthusiasts, and for anyone interested in tropical island natural history.
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TROPICAL ISLAND RECOVERY Cousine Island, Seychelles
Michael Samways, Peter Hitchins, Orty Bourquin, Jock Henwood
A John Wiley & Sons, Ltd., Publication
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This edition first published 2010, © 2010 by Michael Samways, Peter Hitchins, Orty Bourquin, and Jock Henwood Blackwell Publishing was acquired by John Wiley & Sons in February 2007. Blackwell’s publishing program has been merged with Wiley’s global Scientific, Technical and Medical business to form Wiley-Blackwell. Registered office John Wiley & Sons Ltd, The Atrium, Southern Gate, Chichester, West Sussex, PO19 8SQ, UK Editorial offices 9600 Garsington Road, Oxford, OX4 2DQ, UK The Atrium, Southern Gate, Chichester, West Sussex, PO19 8SQ, UK 111 River Street, Hoboken, NJ 07030-5774, USA For details of our global editorial offices, for customer services and for information about how to apply for permission to reuse the copyright material in this book please see our website at www.wiley.com/ wiley-blackwell The right of the author to be identified as the author of this work has been asserted in accordance with the Copyright, Designs and Patents Act 1988. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, except as permitted by the UK Copyright, Designs and Patents Act 1988, without the prior permission of the publisher. Wiley also publishes its books in a variety of electronic formats. Some content that appears in print may not be available in electronic books. Designations used by companies to distinguish their products are often claimed as trademarks. All brand names and product names used in this book are trade names, service marks, trademarks or registered trademarks of their respective owners. The publisher is not associated with any product or vendor mentioned in this book. This publication is designed to provide accurate and authoritative information in regard to the subject matter covered. It is sold on the understanding that the publisher is not engaged in rendering professional services. If professional advice or other expert assistance is required, the services of a competent professional should be sought. Library of Congress Cataloguing-in-Publication Data has been applied for ISBN: 9781444333091 A catalogue record for this book is available from the British Library. Set in 11/13.25pt Times New Roman Printed in Malaysia 1
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CONTENTS
Foreword by Sir James Mancham
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Acknowledgements
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Cousine Island in a world context
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Cousine as a Seychelles island
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Cousine Island’s conservation significance in a nutshell
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How humans nearly pushed Cousine past the tipping point
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The changing seasons
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The lie of the land
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Cousine's rocks, soils and sand The granite The sandstone The sand
The moody sea General characteristics Seabed characteristics The surf zone The intertidal zone
Cousine's green carpet Plant pioneers and colonizers Mown and cultivated communities Grasslands Herblands
Cousine's woody cloak Shrublands Secondary herblands/woodlands Woodlands and forests
27 27 28 30 35 35 36 40 41 43 44 45 46 48
50 50 51 53
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Cousine's vegetation reprieve Underlying philosophy and practical considerations The volunteer programme and monitoring activities Propagation and planting of indigenous plants Bamboo removal Restoration of the coastal plain Casuarina removal Restoration to the south of the pavilion Restoration of the northern plain Overall view of the restoration of the plain
Sponges, corals and the great bleaching event
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Sponges Corals Anemones and zoanthids
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Life in the shallow sea: from shells to urchins Chitons Sea snails Nudibranchs and sea hares Bivalves Octopuses, squids and cuttlefishes Marine worms Barnacles Isopods and amphipods Shrimps, prawns and lobsters Sea cucumbers, starfish, brittle stars and sea urchins
80 80 82 82 83 84 84 85 85 86
Between sea and land: a variety of crabs
90 90 92
Hermit crabs True crabs
Ecological webmasters: terrestrial invertebrates Land snails Earthworms Spiders, ticks and allies Millipedes and centipedes Insects Isopods
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62 62 64 64 66 67 68 69 70 71
97 97 97 98 100 102 117
CONTENTS A rich tapestry of fish life Seychelles fishes Sharks, allies, and attacks on turtles Diversity of bony fishes Fishes of the inter-tidal zone Implications of the great coral bleaching event for the fish
Cousine as a haven for turtles Firstly, a note on amphibians Exploitation of turtles Turtle breeding on Cousine's shores
Of tortoises, lizards and snakes Cousine as a refuge for giant tortoises Geckos Seychelles skink Wright's skink Snakes
Overcoming the extinction of experience: sea bird haven Overcoming the extinction of experience Shearwaters Tropicbirds Frigate birds Lesser noddy Brown noddy White tern Bridled tern Sooty tern
Aquatic and shore birds Herons and egrets The Moorhen Plovers, sandpipers and related shorebirds Crab plover
A truly successful story: endemic land birds Seychelles blue pigeon Seychelles turtle dove Seychelles magpie robin Seychelles warbler Seychelles white-eye Seychelles sunbird Seychelles fody
118 118 118 119 126 126 127 127 127 127 135 135 139 142 144 145 147 147 147 148 151 152 153 155 160 160 162 162 162 164 164 165 165 165 166 169 170 172 172
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FOREWORD
By Sir James Mancham, the first president of the Republic of Seychelles This is my Island in the sun Willed to me by my father's hands All my days I will sing in praise Of your forest, waters and shining sands…… Harry Belafonte In the early sixties when I was practicing law in Seychelles, Harry Belafonte's “Island in the Sun” was perhaps the most popular song among the Seychellois – and perhaps among many other Island people all over the globe. We were cut off then from the rest of the world and often referred to by outsiders as “The Last Lost Paradise.” One morning a young Praslinois, Charles Payet Jr. from Anse Kerlan, Praslin walked into my law office in Port Victoria. “Mr Mancham,” he said. “My father died and left me an Island. It is a very beautiful island but I am getting no income from it. My family and myself have decided to ask you to find a buyer for it as we would like to emigrate to Australia.” “But how much do you want for your Island?” I asked. “No idea whatsoever. I guess if I can get one hundred thousand rupees, I could give you 5% commission on that.”
much do you want for it?” Without thinking too much about the matter, I promptly replied. “One hundred and forty thousand rupees.” “Ok,” he said. “I buy it.” Thus did Mr Payet received one hundred and twenty thousand rupees for his Island – a sum then sufficient for him and his family of five to travel to Melbourne, Australia where on arrival he bought himself a farm with a large colonial house, a land-rover, a dog and a cat as he started a new life down-under. For me twenty thousand rupees at that time represented three trips to Europe and getting to know the world and particularly other Islands of distant seas. Obviously, I have always considered myself fortunate to have been born on a group of islands that was situated in the wilderness of a gigantic ocean more than a thousand miles from anywhere. I am fortunate to have grown up on these far-away Island shores at a time when the Seychelles only link with the outside world, was a monthly call by a passenger-cum-cargo boat. There is an inspiration, majesty to Island life that lifts my spirit and stirs my soul to singing or poetry.
“Well, Charles I have also no idea what we can get for the Island. But let us make a deal. If I get only one hundred thousand, then there is no commission for me. But if I get anything over and above, then we can split this in two.” Charles was very happy with my proposition and we shook hands over it. Two months later a young and suave Italian, Mauricio Raybaudi Massilia walked into the same office. Mr Raybaudi Massilia had become wealthy as a stamps dealer in Rome. After some marital problems, his dream was to find a beautiful starlet to share “La Dolce Vita” with him under the shade of some coconut palms in a far-away Island. “Sir,” he said. “I understand that you are the selling agent for Cousine Island. I am interested to buy. How
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Here on the shores of the Indian Ocean I tell the truth On sandy beaches, on granite soil and rising rocks I can feel and sing my antiquity
Some 40 years after Mr Payet sold Cousine, and after two other subsequent changes in ownership, the Island today belongs to Fred Keeley who acquired it some years ago and who has since made it one of the best kept Islands in the world from a conservation standpoint. In May 1980, the late Prince Bernhard then married to the Queen of the Netherlands who was President of the World Wildlife Fund wrote the preface to a coffee table book I had written entitled – “Island Splendour,” which was published in German and English by Christian Verlag of Hamburg. This is what Prince Bernhard wrote from Soestdijk Palace: “Every Island in the sea is an isolated miniature world. As plants and animals colonize an Island, it becomes an arena in the struggle for survival – or the testing ground of evolutionary change. In fact, every Island has its own system of ecology, its balance of animals and plants, which have evolved in relationship to one another and to their environment. An understanding of their ecologies is vital for conserving world resources. Many Islands have been ravaged beyond repair; some of the most fascinating of Island creatures are beyond re-call. But it is still not too late to save something. That is why I welcome the opportunity of the publication of this book on Private Island to remind owners of Islands worldwide of their responsibility towards posterity. Some years ago, I was privileged to visit the Seychelles and meet Mr James Mancham. Coming as he does from one of the most beautiful Island groups in the world, I think that he is fully qualified to exalt the spirit of Island life.”
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Seychelles can consider it most lucky today that Cousine Island is in the ownership of Fred Keeley – a kind man, whose outlook on small Islands, I know, is similar to that of the late Prince Bernhard. Because of his spirit and philosophy, backed by exceptional generosity – Fred Keeley is able to preserve this gem in our fragile archipelago for the enjoyment of posterity. Sir James R. Mancham, KBE, PhD Founding President of the Republic of Seychelles President of the Global Peace Council of the Universal Peace Federation
ACKNOWLEDGEMENTS This book has been a great pleasure for us to write, as Cousine Island is such an amazing place and exploring what can be done to restore a special share of paradise that otherwise might have been lost. Many have contributed to the task, in particular, Fred and Nell Keeley, whose foresight in having Cousine Island managed so as to conserve the special array of plants and animals, instead of developing it into another insensitive tourist destination, is acknowledged with appreciation, as does his personal interest in the information gathered. Stella Hitchins (née Le Maitre), Researcher, contributed numerous specimens and information, controlled and monitored the introduction of the Seychelles Magpie robin, assisted in all aspects of island management, turtle monitoring and good food, all of which we thank her for. Other Island staff including George and Juliana Souffe, Elize Chetty, Berard Boniface, Kerren Carpin, Percy Talma and Roland Tambara all helped with information and some interesting specimens. David Barraclough (University of KwaZulu-Natal), Corrina Bazelet (Stellenbosch University), Katy Beaver (Plant Conservation Action), Lindsay ChongSeng (Seychelles Islands Foundation), Alain Crosnier (Natural History Museum, Paris), the late Sebastian Endrody-Younga (Northern Flagship Institution), Justin Gerlach (The Nature Protection Trust of Seychelles), Michelle Hamer (South African National Biodiversity Institute), the late Jan Heeg (University of Kwazulu-Natal), Dick Kilburn (Natal Museum), Dai Herbert (Natal Museum), Kathy Gordon-Gray (plant taxonomist), Danuta Plisko (Natal Museum), David Richardson (University of East Anglia), Gerard Roccamora (Island Conservation Society), the late Michael Saaristo (University of Turku), Brian Stuckenberg (Natal Museum), and Rob Toms (Northern Flagship Institution) are thanked for their rapid and professional specimen identifications. Invertebrate identification services were supplied by the South African Museum, Plant Protection Research Institute and the South African Institute for Medical Research.
The assistance of Mark Spalding (World Conservation Monitoring Centre, Cambridge), Kristian Teleki (Cambridge Coastal Research Unit), Geoff Kelly, Graham Byron (Department of Environment, Queensland) and Suzanne Marshall (Division of Environment, Coastal National Parks, Seychelles) in the early coral reef surveys is gratefully appreciated. Luc Grandcourt and Victorin Laboudallon from Praslin Island, Pierre Grandcourt from Mahé and Jean-Pierre Friedli from Switzerland contributed many insights into the early days of life on Cousine Island. Grateful thanks to Ester Ball, Robert Bell, Robbie Bresson, Lex Brunn, Martin Cooke, John Colley, Jamie Copsey, Kathy Dalley, Ros Finlay, Ron and Gill Gerlach, Selwyn Gendron, Paddy Heathcote-Amory, Mark Hitchins, Rob Hitchins, Jan Komdeur, Ken and Femmie Kraaijerveld, James Lawrence, Jean Mortimer, John Neville, Georges and Margaret Norah (also checking Creole names), the late Howard Otto, Janine Samuel, Melinda Samways, Gavin Scott, and Janske van de Crommenacker all contributed significantly in one way or another; many as unpaid and motivated volunteers involved in the physical aspects of the restoration programme. Manda Stander in South Africa initially attended to all the island supplies from the tiniest of screws, tools and equipment to the basic vitals for sustaining human life and then followed the requirements for the construction of the visitor facilities; a logistical challenge that was met with dedication and efficiency. Thank you.
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Thanks to Michael Rands (Birdlife International) for supporting the introduction of the Seychelles magpie robin, and to Nirmal Jivan Shah of Birdlife Seychelles and later Nature Seychelles for interesting discussion, insight and support of Cousine Island's recovery mission together with the initiation the Global Environment Facility Project for improving management of high biodiversity islands (Nature Seychelles and Cousine) GEF island project (Cousine, Cousin and Aride islands). Also to Adrian Skerret of the Seychelles Birds Records Committee for his assistance and verification of some of the migrant species. Thanks to the Ministry of Environment and Natural Resources of Seychelles for their ongoing support of Cousine's restoration programme, and a grant for 'Improving Management of High Biodiversity Islands'.
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Sven Vrdoljak kindly assisted with graphics and editorial activities. We also thank Martin Harvey for his dramatic cover photograph. Other contributions are gratefully acknowledged in the text adjacent to each photograph. René Gaigher, and Kevin and San-Marie Jolliffe, also kindly commented on the manuscript. To Cousine's conservation staff, past and present, Kevin and San-Marie Jolliffe, Dylan Evans, Frankie Hobro, Quentin and Debbie Hagens, James Lawrence, and Paul De Bruyn, thank you for all the energy and dedication that you have put into this project. To the donors of some of the Giant tortoises, Frank and Alexa Collie, Jerry and Mandy Morin from Mahé, Peter and Gay Cummings from Praslin, and Liz Gardner from Cerf Island; a wonderful contribution that these animals should be given the chance to roam freely. Grateful thanks also to the late Danielle St Jorre, Minister of the Seychelles Ministry of Environment, for her tremendous enthusiasm and encouragement during the early days of the restoration initiative. Last but no means least, we also thank Melinda-Jayne Graphics Design for composing the book and Ward Cooper of Wiley-Blackwell for his enthusiastic support of the project.
COUSINE ISLAND IN A WORLD CONTEXT The world is in the throes of a biodiversity crisis, with perhaps a quarter of all species likely to go extinct as a result of human pressure. These extinctions are likely to be particularly severe on tropical islands. Cousine Island is counter-current to this trend. Although once highly degraded, it is now exceptional in a world context, as it has been restored to what research has suggested was its state prior to human impact.
No one is quite sure just how great the current extinction crisis is, nor how deep it will go, nor how long it will last. If McKinney (1999) is right, then at least a quarter of all insects alone will become extinct, which may be as many as two to three million species worldwide. Of course, it is not the first mass extinction but is characterized by being the first one caused by humans. One of the greatest concerns is for tropical areas, which, by the nature of their delicate soils and mycorrhizal interactions are particularly susceptible to major changes in ecosystem character. Small tropical islands are particularly threatened (Denslow 2003; O'Dowd et al. 2003; Primack 2006), as they are surrounded by sea, making much edge in comparison with interior. This large edge/interior ratio means that the island is susceptible to various outside influences such as human, other animal and plant invasions. Such small islands are also prone to abiotic outside effects such as high winds, desiccating effects of dry winds, proneness to extremes of weather and the effects of salt spray. They are also, perhaps surprisingly, often short of water, a well-known fact for castaways. They are also not free of pollution, with Cousine having had oil globules drifting onto the beach on 8 March 1997. On the positive side, outside effects include the allochthonous input of nutrients from seabirds bringing fish for their chicks, dropping food items and defaecating on the relatively impoverished soil (Polis and Hurd 1996).
Another issue is that small islands are spatially limiting. When there is a population increase, whether of humans, wild species, invasive aliens or domestic livestock, unless they migrate, are moved or removed, they will inevitably deplete the natural and indigenous resources. Such a situation can reach a tipping point where there is radical transformation, known as catastrophic regime shift (Scheffer and Carpenter 2003) leading to a different and largely irretrievable ecological state. Such a situation has occurred on Easter Island (Bahn and Flenley 1992). Cousine was almost in this situation in the 1960s, meaning that radical steps had to be taken to reverse the deteriorating situation. Nevertheless, Cousine had one very significant saving grace: it had no rats nor mice. The significance of this cannot be underestimated, as these animals can have a devastating effect on island faunas in many quarters of food webs from herbivorous insects (Smith et al. 2002) to the eggs of birds. Cousine also had relatively little human infrastructure, partly because of its small size (26 ha), shortage of potable water and no permanent harbour. These critical features meant that Cousine was restorable, while at the same time providing a tourist destination of global significance (Klocke and Klocke 2006). In other words, the indications were that the island could be brought back to a perceived 'original' state. This perception was based on triage: all concerted and appropriate efforts would contribute towards the island's ecological integrity (structural and compositional biodiversity) and ecosystem health (functional biodiversity) being restored (Samways 2000). This is a trajectory towards the 'original' state, and of much more conservation significance than regreening or rehabilitation.
Tropical Island Recovery: Cousine Island, Seychelles.1st edition. By Michael Samways, Peter Hitchins, Orty Bourquin, and Jock Henwood. Published 2010 by Blackwell Publishing Ltd.
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A conceptual model of ecosystem restoration triage. There is a gradient from ecosystems with intense-and-frequent, mostly anthropogenic, disturbance and low ecological integrity, to ecosystems with intense-and-very infrequent or mild-at-any-time natural events and high ecological integrity. Urbanization is at one end of this spectrum and the 'original' state at the other. 'Original' is in parentheses because (a) it depends how far back we go in time, and (b) because we can never be completely sure what all the original structural, compositional and functional biodiversity was at any one time in the past. The lost 'original' state is the pristine state, which no longer exists, as anthropogenic impacts reach all parts of the world. Restoration here is a biocentric, deep-ecology view, where there is a genuine aim to bring back all aspects of ecological integrity. The starting point in the decision process is whether to restore or not restore ecological integrity. It does not invoke decisions on whether to regreen, ecologically landscape or rehabilitate. These three have various cultural, aesthetic and engineering components, and not just a biocentric one. There are two extremes of 'doing nothing' (a) where ecological integrity is irretrievably lost (e.g. a harbour for large ships), and (b) where ecological integrity is intact. Where ecological integrity is irretrievably lost, only regreening, rehabilitation or ecological landscaping, but not restoration, is possible. The third prong of triage is the one where ecological integrity is restorable, and is the highest level of biocentricity. Regreening is simply putting back a vegetation cover with more consideration to aesthetics and engineering value than to ecological integrity (e.g. grass cover of road cuttings).
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The maximal ecological integrity value for regreening is roughly at the level of recreational areas, with disturbance ranging from intense and frequent (e.g. mowing) to infrequent and mild. Rehabilitation aims to recover some ecological integrity but has major aesthetic and/or human cultural components combined with ecological considerations (e.g. mine dump rehabilitation, removal of pollutants from a stream). Like regreening, the maximal ecological integrity value achievable through rehabilitation is low. This contrasts with ecological landscaping which deliberately aims to recreate what is estimated to be a 'natural' ecosystem, which may be aesthetic (deliberately or inadvertently anthropocentric) or not (purely biocentric). Carefully planned planting of indigenous trees along roadsides is an example of ecological landscaping. Researched well, ecological landscaping can have great ecological integrity value, at least over time after indigenous biodiversity returns. Ecological landscaping is also of value to greenways, ecological networks and reserves with management. We are then finally left with restoration, which can normally only be truly done on minimally degraded ecosystems (hence the dashed line in the central area of the figure). Restoration aims for the 'original' state, but this is rarely actually achievable (because of, for example, invasive aliens) (hence the dashed line in the lower right of the figure) (From Samways 2000). Cousine also faced one other issue as the restoration process began to unfold. There was no doubt that the invasive alien species had to be removed and preferably eradicated, often with great effort. In the case of some stubborn or re-invasive species, this is an ongoing activity. For others, it just had to be done as an intrinsic part of restoring ecological integrity. Another point of departure was whether Cousine was going to engage, and to what extent, in the preservation of other endemic Seychelles biota, even though it was not known for sure whether they once even occurred on the Island. There are some background issues which influenced the decision. Firstly, it is only in the last few thousand years, a short time in evolutionary terms, that the Island has been isolated, having been part of an extensive landmass only 18 000 years ago, when sea levels were over 100 m lower than they are today (Camoin et al. 2004). Secondly, with such extensive and intensive transformation of the landscape and invasive alien creep on the larger islands (Fleishmann 1995), it was inevitable that some Seychelles endemics on these islands would come under increasing and synergistic threats, as well as being subjected to adverse stochastic impacts. In response, there was a contingency plan for some of these threatened species to be transferred to other, ostensibly safer, islands. Cousine fell into this category, and has since become a very important ark for some significant Seychelles endemics (see Friedmann (1987) for information on the Seychelles flora). The restoration of Cousine has been through several phases, the first of which began in the 19701980s. The approach was ad hoc, and mostly the removal of alien animals such as livestock and cats.
Although poaching of sea birds and turtles was also prohibited, this activity continued at unknown levels. Little was done by way of removing invasive alien plants at this time, nor was there any reduction of the agricultural area on the plain. In the early 1990s, a systematic management plan was implemented, which involved three strategic issues: 1) containing some of the most aggressive alien plants by introducing measures to remove them, 2) containing and removing certain alien plants to increase the open areas for ground-nesting sea birds, and 3) removal of the agricultural plants on the plain. This removal programme, coupled with increasingly strong control of poaching, was automatic incentive for sea birds to return, given good habitat and lack of harassment. The alien plant removal was also coupled with a cultivation programme for indigenous plants that would be destined to replace mostly the agricultural plants on the plain to re-establish the historic lowland forest.
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Once these plants, which were mostly trees, began to establish and form a canopy, they provided an increased nesting area for sea birds that required this habitat. The canopy also increased the foraging area for the introduced passerine birds, as well as providing humid and shady conditions for much of their invertebrate prey. Throughout this latter scientific restoration phase, which continues today, various naturalists and experts visited the island and provided input into inventories of the island and population counts of various key species. This continues today as an ongoing monitoring programme to continually assess the Island's restoration progress. None of these above activities could have taken place without huge contributions from many individuals from many different quarters and with various inputs, covering policy, management and scientific research. The success of the Island's restoration has come about from much commitment and diplomacy, and, above all, a belief in what was being achieved on Cousine was for the good of conservation. This also meant that opportunities were not just on the Island itself, but also for the Seychelles in general, and as a hallmark for tropical island conservation globally. All these participating individuals are gratefully recognised for their contributions in the Acknowlegements. Without them, Cousine would not have been the success that it has been.
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While this book is about the restoration of Cousine Island, a major event took place in 1998 which stunned the world, with Cousine near its centre. Starting in January 1998, shallow water sea temperatures suddenly increased across wide areas of the Western Indian Ocean, with sea temperatures around Cousine being recorded which were sometimes consistently 2-3° C above the average for that time of year (Samways 2003; Samways and Hatton 2001). The effect was that many of the hard corals effectively overheated and ejected their symbiotic algal zooxanthellae, which supply energy to the coral through photosynthesis. This resulted in many of the corals turning white, known as bleaching, with massive repercussions on the reef structure and on the interactions between many species living on the reef (Graham et al. 2006). Details of this great bleaching event were recorded and are described and illustrated here. No such major bleaching event has occurred since 1998, and we record here some aspects of the recovery of the reef and emphasize its dynamic nature over time. We will now move on to describing, in as much visual detail as possible, both the natural history (see also Bowler 2007, Hill and Currie 2007) and the restoration of Cousine: how it was done, and what it entailed. But first we must consider some geographical and physical background as the dynamics and characteristics of these are an important background for the restoration process which took place.
COUSINE AS A SEYCHELLES ISLAND
The Seychelles archipelago is made up of 115 islands (see Tingay (1995) for a good, brief introduction to Seychelles). Forty of these, the inner islands, are montane and granitic. The others are low sand cays on sea-level coral reefs, or of reef limestone only slightly elevated above the sea. The granitic islands are about 930 km north of Madagascar and 1600 km east of Africa. They lie between 4-5 degrees latitude south, and 55-56 degrees longitude east. Stoddart (1984) and Richmond (1997) provide coverage of Western Indian Ocean wildlife, while Gerlach (2003b) gives an overview of the biodiversity of the Seychelles, and Bowler (2007) and Hill and Currie (2007) are good wildlife guides.
Medicinial plants are covered by Gurib-Fakim and Brendler (2004), flowering plants by Friedmann (1987) and Robertson (1989), marine shells by Jarrett (2000), shell-less slugs by Gerlach (1998a), millipedes and centipedes by Gerlach (1997), cockroaches by Roth (1996), orthopteroids by Matyot (1998), hawkmoths by (Matyot 2005), Lepidoptera by Desegaulx de Nolet (1984) and Gerlach and Matyot (2006), ants by Gerlach (1998b), spiders by Saaristo (1999), holothyrid mites by Gerlach (1995), coral reef fishes by Lieske and Myers (2001), birds by Skerrett et al. (2001) and Sinclair and Langrand (2006), and mammals by Gerlach (2006). Seychelles Red Listed species are summarized by Gerlach (1997) and Gerlach et al. (2005).
The Seychelles archipelago has a distinctly tropical location in the Western Indian Ocean. The central group of islands are granitic peaks emerging from the sea.
Tropical Island Recovery: Cousine Island, Seychelles.1st edition. By Michael Samways, Peter Hitchins, Orty Bourquin, and Jock Henwood. Published 2010 by Blackwell Publishing Ltd.
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Geologically the Seychelles islands are part of the Seychelles bank, an underwater platform of some 31 000 km2, with water depths of mostly less than 60 m. The shoal is surrounded by deeper oceanic water. The 650 million-year-old continental granitic rocks were originally part of the super-continent Gondwanaland. About 135 million years ago, Gondwanaland then split apart. The present areas of Africa, Madagascar, South America, India, Antarctica, Australia, New Zealand and the Seychelles were consequently formed. The Seychelles granitic islands are the only isolated oceanic granitic islands in the world. The largest of the islands are Mahé (145 km2) and Praslin (35 km2), rising to elevations of 914 m and 427 m above sea level respectively. Cousine Island is about 26 ha and rises to just under 77 m, and is effectively a mountain peak. The Seychelles islands are home to many plants and animals which are endemic to the islands. They are derived from species existing on Gondwanaland before it split up, as well as from earlier immigrants from the neighbouring continents. Humans settled in the Seychelles during the middle of the 18th century, and brought with them many species which have since established permanently (Fleishmann 1995). Humans have had other major impacts. Whole forests were cut down and in their place a host of alien crop and ornamental plants were gradually introduced. These occupy much of what was indigenous forest. A number of indigenous animal species have consequently become extinct, and many others are on the brink of extinction. The introduction of alien animal species has also directly contributed to the decline and extinction of the indigenous fauna. This has come about from naiveté to foreign predators, often so apparent in indigenous organisms on small and isolated islands. Formerly two large vertebrates, the Salt water crocodile (Crocodylus porosus) (extinct by the mid 1800s) and the Dugong (Dugong dugong) occurred in the granitic Seychelles, and presumably would have been occasionally seen off the shores of Cousine Island. Similarly, the Robber crab (Birgus latro) may once have occurred on the Island, as it was formerly known from the granitic Seychelles.
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Re-introduction of the crab is always a possibility, after due consideration to possible human/animal conflict in the case of the crocodile and the big crab, although in the case of the crab, such conflict is likely to be more theoretical than actual. Conservation of the remnants of the animal and plant diversity of the Seychelles requires the full and committed attention not only by the Seychelles Government, but also by the people of the Seychelles and by the international community. Each of the individual granitic islands must be considered as an important part of overall Seychelles faunal and floral biodiversity. Indeed, each island contributes to the whole in its unique way as a custodian of the biological systems which are part of the Seychelles heritage (see Gerlach et al. 2006). Cousine is among this family of unique islands. It could have become simply another tropical island, like so many, radically transformed and with little hope of recovery. Yet with foresight and dedication, it has become a prime jewel in the crown of restoration projects. Today, Cousine Island appears to be one of the few islands in the tropical world which has always been free of invasive and destructive rats and mice. It has also been cleared of the most offensive alien plants, and now has a carpet of natural vegetation supporting an amazing array of birds and other wildlife. What is so striking when first stepping onto the Island, is how unafraid the birds and many other animals are, with many virtually within touching distance. Thus, it is one part of the tropical island world that has rescued the 'extinction of experience', where truly wild natural history is returned to our senses as well. As a result, it has become a destination of special significance for naturalists. This book documents the natural history and ecological restoration of this enchanting and beautiful island that has been largely returned to the world in its full primeval and natural beauty.
COUSINE ISLAND CONSERVATION SIGNIFICANCE IN A NUTSHELL Cousine Island, at 4°21'41" latitude south and 55°38'51" longitude east, is just over 1 km long and 400 m wide at its widest point, and 25.7 ha in extent. Its small size belies its importance in terms
of the conservation contribution it makes to the Seychelles and the world in general. It has the following noteworthy features:
It is one of the only granitic islands in the Seychelles over 25 ha that is entirely free of alien mammals. This is a major factor in the conservation of island biodiversity. There are few islands, if any, in the world with this status.
It has several species of nesting seabirds, and is one of the only four granitic islands with major sea-bird colonies. The Lesser noddy, the most prolific breeding species on Cousine, is a subspecies found only in parts of the Western Indian Ocean.
It has lowland forests of Pisonia, Figs, White Hernandia, Pacific almond, Coast cordia and Rosewood. These forests have been largely destroyed on the main granitic islands. Pisonia occurs as a forest community dominant on only three granitic islands: Aride, Cousin and Cousine.
It has a group of 20 free ranging Aldabran/Seychelles giant tortoises rescued from captivity.
Tropical Island Recovery: Cousine Island, Seychelles.1st edition. By Michael Samways, Peter Hitchins, Orty Bourquin, and Jock Henwood. Published 2010 by Blackwell Publishing Ltd.
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It has breeding populations of six endemic land birds, including the Seychelles warbler, Seychelles magpie robin, Seychelles white-eye and Seychelles fody, all of international conservation importance.
It has five of the 13 Seychelles endemic lizards, and one of the two endemic snakes. Of these reptiles, three are considered important in conservation terms, owing to their restricted distribution. These are Wright’s skink, Seychelles wolf snake and bronze gecko.
It provides nesting beaches for Hawksbill and Green turtles, both internationally important as species in great need of protection.
It has coral reef habitats for a host of marine animals.
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It is a feeding area for the endemic Seychelles fruit bat. Between 200 and 500 bats visit Cousine each year to feed on wild fruits such as figs.
Because of concerned and directed management under private ownership, it contributes to effective conservation of Seychelles biodiversity and encourages research into biodiversity and the good management of the environment.
It contributes environmental issues in the Seychelles through dissemination of popular and scientific information, and through selective visitor programmes and the Conservation and Education Centre on neighbouring Praslin.
Cousine has never had a rat, mouse or crazy ant infestation which has caused so much devastation on tropical islands elsewhere. The strict quarantine measures on the island are to prevent these, and other potentially serious pests, from arriving.
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HOW HUMANS NEARLY PUSHED COUSINE PAST THE TIPPING POINT By the 1960's, Cousine Island was in a state of major decline. Nevertheless, it retained natural soil and biological capital among the granite rocks, and enough to initiate recovery of the island, so long as extensive agriculture was stopped, alien animals and plants removed, and poaching halted.
It is not known when humans first visited Cousine Island. Earliest records are of the presence of the tree Pisonia grandis (known locally as Mapou) on Cousine during 1787. A French ornithologist, M.E.Oustalet, collected a Cattle egret on the Island in 1878. There is no evidence that there was any digging of guano for phosphate extraction, which started in 1891 in the Seychelles. There was also no extensive planting of cinnamon or vanilla. Although Cousine is not a large island, significant coconut plantations were nevertheless established. Coconuts were a common component of the coastal vegetation of most of the Seychelles islands when Europeans first colonized them in the early 1600s, and these were used to establish plantations farther inland from the 1850s onwards. On Cousine, various other agricultural practices were also introduced, which together, by the 1960s, had led to serious deterioration of the Island. It was, by that stage, an overgrazed and barren island with little more than coconut palm trees and a plantation of Casuarina trees, a variety of smaller alien plants and some disturbed patches of indigenous trees.
Cousine Island as it was in 1960, largely denuded of vegetation and in a state of major decline.
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Tropical Island Recovery: Cousine Island, Seychelles.1st edition. By Michael Samways, Peter Hitchins, Orty Bourquin, and Jock Henwood. Published 2010 by Blackwell Publishing Ltd.
The first known owners of the Island were a Seychellois family, who bought it in 1923. It then changed hands nine times, mainly among Seychellois owners until, early in 1971, when it was bought for £40 000 by a German consortium of three owners, who formed a company, the Polar Star Company. Until 1971, there were between three and eight people resident on the Island. There were three houses at the time, with Casuarina branches supporting corrugated iron roofing. Pirogues (long, hand-made rowing boats) were used for general transport. Work on the Island was centered on the harvesting of both natural and planted products. Agricultural development of the island no doubt was always limited by shortage of freshwater. Indeed, the only freshwater available was drawn from a well, now defunct, and also from a series of concrete tanks that collected seepage water from the north hill. The risk has always been that the freshwater, which is only a wedge overlying the saline groundwater, is in very short supply. Too much abstraction of the freshwater induces a landward movement of saline groundwater towards the extraction points. That is why today as much rain water as possible is captured as roof run-off.
As on many small tropical islands, water is often a limiting factor, as indeed it is on Cousine. In former times, the only available water on the Island was from this well, no longer used. Today, water is gathered as run-off from the roofs of the newer buildings. Natural harvesting included that of Sooty tern eggs. The Island's saddle and the North-west point, parts of the North hill and part of the south-west coast were kept clear of vegetation to maintain the historical breeding areas for the terns. The hill woodland was regularly cut down to provide open nest sites for the Sooty terns.
In a diary entry by M. Armand Durand on the 16 March 1949, it was mentioned that 12-20 “kerosene cases” of 700 eggs (presumably mostly Sooty tern) representing 8 400 to 14 000 eggs each, were harvested and traded for two cents per egg on Praslin. Another entry, this time by M. Charles Julien Payet on 5 November 1952, mentions that 75-100 cases (52 500 to 70 000 eggs) were harvested for export from the Island. This was clearly such a profitable, yet unsustainable, enterprise that during the egg-harvesting season, up to ten people lived on Cousine. During the early 1960s, workers used a length of cord attached to a rock which they used to swing around and throw at seabirds to kill them. The story also goes that the owner of the Island at the time was so determined to put an end to competition with Cousine's sister island, Cousin, that piles of Sooty tern feathers were used to create smoky fires, and when the prevailing wind was from Cousine to Cousin, the smoke used to drive the birds away from Cousin. But the mean deed had its adverse consequences. When the wind changed direction and blew over Cousine instead, the resident Sooty terns were forced to leave in search of nesting sites elsewhere. By 1971, the terns no longer bred on Cousine, either because of the continuous, sustained harassment, or because the breeding habitat became unsuitable through lack of management, resulting, for example, in overgrowth by fast-growing plants like Coromandel. There were also, prior to the 1960s, dogs (a skull found on the Island verifies this) and cats on the Island, which would have harassed the birds. Shearwater chicks were also collected from their nest burrows among the rocks, both for food and for sale. Up to 8 000 chicks were taken per season, and during the last known harvesting year, 1971, an estimated 3 000 were collected. This was considered by harvesters as low in comparison with previous years. Adult shearwater numbers were also depleted by harvesting, with several thousand being taken annually from Cousine. Skeletal remains of shearwaters found in the dunes on Cousine testify to the past slaughter. The shearwater population on Cousine today is probably very near what it was prior to human impact, with a strong colony of about 30 000 pairs breeding safely among the retreats in the rocks.
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Shearwater bones, exposed by sea erosion of the beach dune, are testament to past slaughter of these much sought-after birds for the kitchen.
Hawksbill turtle scutes, called 'kare' and used in jewelry, found under a rock overhang on Cousine Island in 1995.
Green turtles were harvested for meat and the Hawksbill turtle was killed for both meat and its shell ('kare'), which was sold for the manufacture of jewelry. The last turtle poaching incident on Cousine was in 1995.
Planted products included fruit such as bananas and custard apple, vegetables, cotton and tobacco. Although the tobacco (planted from 1946 onward) was not of good quality, up to 10 000 plants, yielding a ton of tobacco per annum, were established. Copra and coconuts were also harvested. All the crops were planted on the coastal flatlands on the east side of the Island. Products were transported, mainly to Praslin, by pirogue or schooner. The first Casuarina trees were planted between 1946 and 1948, and further plantings took place during the 1950s. The stalks of the introduced Guinea grass (Panicum maximum), Fatak in Creole, were used to make brooms, and up to 100 were made per month and sold on Praslin. Fish were also caught and salted for sale. During the time that the Island was owned by the Polar Star Company, the first attempts were made to restore the Island. The taking of birds and their eggs was stopped, as was fishing and the poaching of shearwaters, turtles and other wildlife. The company also took precautions to prevent spear-fishing, turtle catching and damage to the reef. In addition, there was a strict rat-control protocol from 1964 to 1974, where all cargo deliveries were inspected, for possible invasive rats, on the beach prior to being carried into the hinterland. During the construction stage from 1971 to 1974, there were 30 people living on the Island, and shearwaters were very much part of their diet.
These carapace remains of a Hawksbill turtle on Cousine Island illustrates the former impact on these animals which were harvested both for meat and for jewelry manufacture.
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The apartments after they were first built in the 1970s Today they are largely obscured by forest. In the foreground is the coastal plain which was highly disturbed by agricultural activities at the time.
Poaching has always been a problem for Cousine. Shown here are some confiscated Wedge-tailed shearwater carcasses on Cousine in 1996. Risks are taken by poachers because the birds are highly appreciated in traditional Seychelles cuisine.
The Polar Star Company built apartments, designed by a Swiss architect, Jean-Pierre Friedli, who spent much time on Cousine supervising the project. The endemic, very scarce Seychelles warbler, introduced to Cousine as an early conservation measure during the 1960s, was present on the Island until about March 1973. However, following blasting in the granite hill area for building the apartments, no further warblers were seen, and by 1977 all the birds had disappeared.
Beach activity about 1970, when some restoration of Cousine was just beginning. A report on the Island's condition in early 1972 indicated that the coastal plateau was a poorly managed coconut plantation with extensive secondary scrub areas. This plantation had evidently been in place for many years, as a Seychelles Government report, dated 1940, mentions that, at the time, Cousine was covered with coconut plantations (Diamond 1975).
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In the 1970s, the plain was largely a coconut plantation, which also went to higher ground. In the 1970s, a portion of Cousine of about 2 ha was being cultivated for vegetables, fruit, and tobacco. A pig and two dogs were also present. By 1983, there were a number of pigs in sties, three cows, 150-200 chickens, ducks and many cats. Of concern, was the large impact such a large number of chickens were having on the invertebrate and skink populations. The cattle and pigs were removed by 1992, as were poultry, except for some feral fowls which eked out a precarious existence on the Island until the last one was finally removed in 1999. Very little bamboo was present. The cats that had bred from one pair had reached such numbers in a feral condition that the Polar Star Company commissioned a cat eradication programme in an attempt to secure what remained of the natural bird populations, which were so vulnerable on such a small and sensitive island. Eradication was carried out by a Seychellois, Victorin Laboudallon, who used traps and the poison "1080" to destroy the 73 known cats during five eradication forays between April 1983 and June 1985. As it turned out, a total of 81 cats were destroyed, and the island was cat-free once again.
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A typical feral cat that once occurred on Cousine Island, causing devastation of the indigenous bird populations. Laboudallon examined the stomach contents of the cats he had killed, and found that 67 (over 80%) contained mainly Audubon's shearwater chick remains. The cats had also eaten small numbers of Wedge-tailed shearwaters, Wright's and Seychelles skinks, Ghost crabs, and a White tern.
The branches of some indigenous trees (mainly Pisonia (Pisonia grandis) and figs (Ficus spp.)) were used as fodder for the pigs and cattle. The cattle, which were in very poor condition, were tethered to stakes and left to graze the ground bare before the stake was removed and placed elsewhere. An indigenous ornamental plant, the Slipper flower (Pedilanthus tithymaloides), often used by Seychellois to keep evil from their homes, was also present.
The Slipper flower: said by the local Seychellois to keep evil from their homes. By 1991, many alien ornamental plants had been introduced, including Yam, Croton, Bougainvillea, Silver queen, Mother-in-law's tongue, Sisal and Prickly pear cactus. Sisal and Prickly pear were of major concern as they were capable of spreading throughout the Island. Two patches of pineapples were established on granite on the north and east facing lower slopes of the North hill. A number of fruit trees, mainly bananas, citrus, Papaya, Soursop and Custard apple, were introduced. Papaya seeds are spread by birds and readily grow in areas outside the garden site. Grenadilla and Guava were also present, both of which are potentially invasive.
Pineapples formerly growing in shallow soils on a rock ledge of the North hill.
Following a change of ownership in 1991, there was a very active clean-up of the Island . A modern infrastructure, with well appointed staff accommodation, workshops, five hours per day of electricity in the evenings, was established. Transport lines for a tractor, other earth-moving equipment and small electric vehicles, were also introduced. Controlled sewage and garbage disposal systems were also established. Six boreholes were sunk in 1992, of which only three produced freshwater, and one of which yielded truly potable water. A conservation programme was initiated in January 1995, with goals set by a mission statement that gave guidance for future conservation actions on the island. One of the first steps was to remove alien plants and control weeds, especially of those known to be invasive. This then freed up areas for the re-establishment of indigenous plants.
Cousine Island Mission Statement "To promote and practice nature conservation and the wise use of natural resources of the island and its surroundings"
Seventy eight alien plant species were recorded on the island, of which 31 species have been eradicated, and 21 species are utilized by humans in one form or another. Of the remaining alien plants, 26 species are being controlled or in the process of being eradicated. These remaining plants are constantly monitored, especially the invasive species, such as Papaya, which has the ability to spread into the forested areas. Cultivated plants are grown in a strictly designated area of 0.3 ha. The remains of the old coconut palm plantation are in the process of being eradicated, with removal of mature trees which are not suitable as nest sites for the Brown noddy. There is also a programme of removal of germinating seeds (coconuts) beneath the mature trees.
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However, there is also a programme of intermittently establishing a small, controlled population of coconut palms along the beach dune
crest, their natural habitat, to provide nesting sites for Brown noddies and food resources for the island's kitchen.
. Brown noddies claiming their nest site in a coconut palm.
Preparation of coconuts for consumption: a traditional activity on Cousine Island, as on many other tropical islands. The pole is a piket koko, used for dehusking the coconut, and the tool, the lerap koko, which is used for shredding the inner flesh.
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While alien plants have been controlled, certain endemic species are being introduced either to increase the chances of survival in the Seychelles in general, or because they appear to be important for aspects of ecosystem function, such as being a food supply for endemic animals. Fifteen Seychelles endemic and indigenous tree or shrub species have now been introduced, including five species which were not indigenous to Cousine, but were required as food plants for the subsequent introduction of the threatened Seychelles white-eye. Another introduced tree, accepted for introduction, as it is a Seychelles endemic and listed as globally threatened, was Wright's gardenia (Rothmannia annae). It required wider establishment to ensure its long-term survival. Almost all of the indigenous trees and shrubs were raised from seeds and cuttings in a specially-constructed nursery on the Island. All of the introduced plants, with the exception of those stipulated for introduction of the Seychelles white-eye, were relocated as seeds or seedlings that had all the soil removed from their root systems as a quarantine measure. One of the adverse side-effects of re-vegetating the previously cultivated areas has been a reduction of species of plants and animals adapted to open areas. Swamp grass (Paspalidium geminatum), for example, has become extinct on the Island due to the shading effect of planted Terminalia trees. Birds, such as the alien Barred ground dove and the Madagascar fody have over time also become scarcer as the open habitat has dwindled, with a lower production of grass and herbaceous seeds. A problem that still remains is the inadvertent introduction of alien plants. Seeds and fruits of alien plants are also washed up on the beach, and are probably also brought onto the Island by birds from neighbouring islands. In 2007, pantropical Yellow necklacepod (Sophora tomentosa) was washed up and established on the dune crest.
Seeds on the high-tide drift line. Seen here is Coconut palm, and indigenous Alexandrian laurel (Takamaka), Rosewood, Pacific almond, and Looking-glass tree.
The Indian mynah, an alien bird, apparently first appeared on the Island during the 1970s, but through continuous removal of individuals, has been almost eradicated from the Island. There are small fluctuations in this population owing to periodic immigration from Praslin island.
The Indian mynah is an aggressive alien towards indigenous birds and is constantly removed from Cousine.
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The Barn owl, also alien, occasionally makes its way to Cousine from Praslin, but has not established owing to strict control measures. Fringing reef destruction occurs when local fishing and leisure boats cast their anchors and place their heavy fish traps. Reef damage also arises when octopus hunters lever up the coral. Since the sea is open to use by anyone, it is not possible to prevent such damage through law enforcement. This is of concern for the reefs of the Seychelles, with signs of greatly reduced lobster, octopus, sea cucumber and certain fish populations in some areas.
In the Seychelles, sea shells and corals have been exported for some decades. The trade is apparently much smaller today than it was during the 1950s, with most marine shells today being sold mainly to visiting tourists. In many places in the tropics, the collection of seashells has led to reef damage and consequent loss of biodiversity. Some shell-bearing molluscs are now protected by international law, including the Giant triton. On Cousine, the collection of living molluscs for sea-shell souvenirs is prohibited, and the removal of dead shells is discouraged.
The enormous Giant triton, is now protected under international law of the Convention on Trade in Endangered Species (CITES).
Traditional fish traps being set on Cousine's fringing reef. In former times, beach crabs were harvested and indiscriminately killed in large numbers on Cousine. This practice was halted in 1995 as part of the conservation management plan.
Typical displays of harvested shells, and still practiced in some areas of the Seychelles. A traditional bamboo-constructed fish trap, weighted with rocks on the fringing reefs.
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The ongoing sea-turtle protection and monitoring programme has resulted in an increase in numbers of visiting female turtles over the last few years, principally through control of poaching. This is encouraging for the future of turtle conservation, especially since it appears that the Hawksbill turtle in the Seychelles is genetically different from other populations. The Seychelles hawksbill turtle nests predominantly during the day, a rare occurrence for any species of sea turtle. To enhance conservation of the Giant Aldabran tortoise, a small herd of 21 individuals was established, with 20 surviving today. They were introduced over time as both purchases and donations of captive individuals, often having been housed under appalling conditions, so as to give them the freedom that they so rightly deserve. They play an extremely important role in the natural distribution of seeds.
The introduction of the Seychelles magpie robin to Cousine Island on 2 November 1996. Of great importance for the continuing maintenance of biodiversity on the Island is to keep it free of destructive alien animals. Cousine has a strict rodent and ant protocol, implemented in 1995. Rats, mice and ants have been the cause of reduction of native wildlife on a great number of islands, and Cousine, Cousin and Aride were the only granitic islands in the Seychelles without rats. Other islands have now been added to the number of rat-free islands, having undertaken extensive and expensive rat eradication programmes. Thankfully, Cousine Island also has no mice, nor the Crazy ant (Anoplolepis gracilipes), which has caused so much havoc elsewhere in the Seychelles. Fruit bats are captured on the larger islands using fine nets suspended between trees. Once captured, the bats are kept in cages for exhibition to tourists and as a delicacy for curry dishes. These bats, while only foraging visitors to Cousine, are strictly protected on the Island.
Dispersal of seeds, in this case Pacific almond, by defaecating giant tortoises.
Among the most exciting and rewarding conservation successes has been the establishment of breeding populations of the Seychelles warbler, Seychelles magpie robin and Seychelles white-eye. All these species are on the World Conservation Union (IUCN) Red List of Threatened Species. In this respect alone, Cousine has contributed greatly to the overall biodiversity conservation efforts of the Seychelles. Captive Seychelles fruit bats on Mahé Island, possibly destined to become 'bat curry'.
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Cousine Island's policy of encouraging research and monitoring of the ecosystems and their components has been immensely beneficial for conservation of the Island. Projects have been on vegetation, birds, reptiles, fish, invertebrates and climate, as well as on subjects such as beach dynamics, soil formation and reef condition. Not only have Seychellois been involved in these ongoing projects, but so have researchers from Australia, Finland, France, Britain, The Netherlands, New Zealand, South Africa, and the United States. The end of the 1990s saw the beginning of a low level of ecotourism on the Island, when the Seychelles Government granted a certificate of approval for the operation of a small, luxury hotel. The purpose of this was to generate funding for supporting the overall conservation programme. A maximum of eight to ten tourists are accommodated in four villas, and other relevant support infrastructures have also been established. This development requires considerable attention to the sensitivity of the natural ecosystems. An environmental impact assessment and a management plan were produced, and a set of island rules developed. All are designed to maintain the natural ecosystems, provide sanctuary for an amazing array of wildlife, as well as to maximize human enjoyment of, and education about, these natural treasures. However, as with any form of development, there is the potential for some conflict between humans and wildlife, with perhaps the greatest challenge being to supply power to the villas and associated infrastructure so as to provide the comfort that international tourists expect, despite being in such a natural setting. Alternatives to importing diesel fuel for generators are continually being investigated. Prior to the construction of the tourism infrastructure on Cousine, strict quarantine measures were introduced. While quarantine was in place even prior to that time, the building activities posed a particular risk that mice, rats, cockroaches and crazy ants could be introduced. All arriving boats used during the construction phase, where possible, were moored offshore and thoroughly inspected. Even today, all small boats bringing visitors and island supplies are closely monitored to ensure that no further invasive
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alien species arrive on the island. Helicopters land only for a short while to allow quick disembarkation of visitors and cargo to reduce contamination risk. All cargo is inspected for alien organisms. Littering of the Island and the washing up of domestic refuse from ships is an ongoing, although relatively minor, issue, nevertheless
Wherever possible, boats which were used in the construction of the tourism infrastructure were moored offshore. This was not always possible, but in all cases the craft were thoroughly inspected for possible invasive alien stowaways, especially rats, mice and crazy ants. Today there is still a strict quarantine protocol, with all helicopters and boats being subject to quarantine. The effect of humans on the ecology of Cousine Island has been both positive and negative. It reflects, in a microcosm, situations elsewhere in the world. With the conservation of natural systems being vital for a balanced, healthy society, Cousine has been a leader in showing what can be done when restoration is actively pursued.
Such littering can also cause death of endemic species such as the Seychelles skink pictured here
THE CHANGING SEASONS All the granitic islands of the Seychelles have a tropical, humid climate. The relative humidity is between 75% and 80%. Mean monthly temperature varies from 25.7 to 28.7°C with average diurnal ranges being 3 to 4.2°C.
Known temperature extremes are 19.3°C and 33.3°C. The coolest months are July and August, and the hottest are April and May.
Storm approaching Cousine Island. Annual rainfall and length of dry season vary considerably from one Seychelles island to another. Highest rainfall occurs at highest elevations. Up to 5 000 mm per year has been recorded from the Mahé highlands. Cousine's annual rainfall has varied from 1 462 mm to 2742 mm, with a mean annual rainfall of just under two metres, characterized by much variation in any single month from one year to the next, making 'dry' and 'wet' months very unpredictable. Evidence is that this unpredictability, especially on a naturally dry island like Cousine, has been a strong selection force on the organisms living on the Island, and has played a large role in shaping island ecosystems. It has also been a consideration during restoration, with newly-established plants being given temporary irrigation to ensure establishment.
Although rainfall has been measured only in recent years, from1993 there are notable monthly fluctuations and extended dry periods. Because of limited surface freshwater, these dry periods may be critical to the survival of some plants and animals. While extended dry periods are tolerated by species indigenous to Cousine, they may not allow longterm survival of introduced species, even those endemic or naturalised in other parts of the granitic Seychelles. An example of this is the introduced Red achatina land-snail of Africa, common on Praslin and Mahé. Only uninhabited shells of this species are now found on Cousine, denoting an invasion of the species onto the Island, a period of population growth and distribution, and then local extinction, possibly because of an extended dry period, or a combination of drought and other factors.
Tropical Island Recovery: Cousine Island, Seychelles.1st edition. By Michael Samways, Peter Hitchins, Orty Bourquin, and Jock Henwood. Published 2010 by Blackwell Publishing Ltd.
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Red acatina land snail shell (top left), an invasive species, once present on Cousine but now extinct on the Island due possibly to extended dry periods. Also present are the bones of harvested Wedge-tailed shearwaters exposed in an eroding dune. The longest continuous dry period recorded for Cousine was 61 days during June to August 1993, while periods of 30 to 40 days are not uncommon during any dry season. A dry period (rainfall less than 100 mm per month) varies from year to year, but is usually between June and December, with a consistently wet month (September) in between. This did not hold true for September 1997, which was dry, and for August (usually a dry month) in the same year during which 579 mm of rain fell in six days. South-east trade winds (Trades) cross the Seychelles from May to October. Lighter and more variable north-west monsoon winds (Monsoons) are from December to March. Winds are variable, with frequent calms during the transition months of April and November. Highest mean wind speeds are June to September on Mahé (13.9 to 17.1 km per hour during the south-easterlies), and for the rest of the year, mean wind speeds range from 5.9 to 10.4 km per hour.
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Even a small, nominally waterless, island like Cousine can flood after torrential rain. This picture, taken on 17 August 1997, is the result of a 525 mm downpour. The great tsunami of December 2004 reached the shores of Cousine but did no damage of any concern. Tropical cyclones have not been recorded for the granitic Seychelles, although strong winds frequently occur for short periods, especially during storms. Sometimes waterspouts may be seen.
The sea turtles nest mainly when the beach is stable or is increasing in size. These are good conditions for the safe hatching of turtles egg clutches. When beaches are eroding strongly, nests can be washed away or destroyed by inundation with sea water.
A waterspout moving towards Cousine from the north-west.
Turtles normally come ashore when sea conditions are safe, but when the weather changes unexpectedly, there are always risks associated with a safe return to the sea.
The power of a waterspout is enormous as it lifts tons of water into the air. It also makes an enormous noise when it suddenly drops its water load. The weather patterns have a strong effect on the Island's plants and animals. Rain influences plant growth and animal survival, and wind affects pollination of plants, causes damage to trees, retards plant growth in areas exposed to salt spray during south east Trades, deflects flying animals, and changes sea currents and wave action. Some of the physical, climatic and biological changes on the Island appear to be strongly linked. For example, Lesser noddy nesting co-incides with the normal dry period during the Trades, when there are moderate sea salinities and sea temperatures of 23-27° C. These conditions lead to a good supply of food in the form of small shoaling fish.
Hawksbill turtle nest exposed by the sea. The common Diadem butterfly (Hypolimnas misippus) normally appears for a few weeks during March and April. After the high rainfall of August 1997, the butterflies first appeared in December and January, probably in response to early growth of some of its food plants, and then made a second appearance at its normal time two months later.
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Monthly average rainfall based on 11 years (1995-2005), with minimum and maximum recorded figures during these months, illustrating the huge variation from one year to the next.
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THE LIE OF THE LAND
Cousine Island seen from its sister island,Cousin. The landscape of Cousine Island is strongly influenced by its rock formations, dominated by the ancient granite which forms the main part of the Island. The highest point is the top of the North Hill, which rises to just under 77 m above sea level, while the South Ridge reaches 40 m at its
highest point. The west, leeward, side is largely small cliffs and boulders, while the eastern, windward, side is largely beach.
Topographical features and infrastructure of Cousine in 2007. Tropical Island Recovery: Cousine Island, Seychelles.1st edition. By Michael Samways, Peter Hitchins, Orty Bourquin, and Jock Henwood. Published 2010 by Blackwell Publishing Ltd.
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Cousine Island viewed from the South ridge, looking across the Saddle to the North Hill in 2007 after restoration of the plain. The seasonal currents and wind-changes affect the beach profile greatly, while the buildings on the east coast, conspicuous from long distances, affect the appearance of the natural landscape. Both the removal of alien vegetation and the introduction of indigenous vegetation on the Island have altered its profile. The early removal of natural vegetation from the flatlands, for establishment of coconut trees and Casuarinas, had a major impact.
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Because the Island is small, even relatively minor changes due to development, or the alteration of vegetation communities, can have a considerable effect on its profile and appearance. However, the long-term aim has always been to restore it to its original character. To this end, indigenous coastal vegetation has been restored, and all invasive alien species are being continually removed outside the allocated garden/workshop area. Coconut trees are also being removed from the hill summit, as they give an unnatural island profile. They have, nevertheless, been retained along the shoreline in low numbers to provide nest sites for the Brown noddy and supply the Island with coconuts.
COUSINE’S ROCKS, SOILS AND SAND Cousine Island is composed mostly of basal granite formations, overlain on the east coast by phosphatic sandstone. These formations are covered to various degrees by soil and sand, and of remarkably variable depths. Granite rocky shores, notable for their beauty, are not extensive on a worldwide basis. They are wellrepresented on Cousine, and emphasize that the Island is essentially a hilltop of granite, or inselberg, which has become drowned and isolated with the rise of sea level over the last 15 000 years, and at periodic intervals prior to that (Camoin et al. 2004).
The granite
The North Hill has an amazing array of rainfallweathered rock formations.
The pre-Cambrian granite, 650 million years old, is among the oldest exposed insular rock in the world. It is pink with narrow aplite veins, typical of the Praslin-type pink granite, as opposed to the Mahé island-group brown granites. The pink granites are often characterized by a variously weathered, rusty red-brown, lateritic material on their surfaces, which penetrates into fresh granite along fractures. The granitic rocks have endured weathering over many millennia, which accounts for the parallel ridge-and-trough appearance of granite exposures. These grooved and fluted surfaces are known as rillenstein. With additional horizontal weathering and erosion, they form rockpiles, known as nubbins (Johnson and Baarli 2005). When horizontal weathering takes place, it leads to piles of boulders called nubbins, which, in time, topple.
In the Seychelles, basalt and dolerite dykes (when hot igneous rock has penetrated fissures) and sheets occur in this granite. Both dykes and sheets have clean intrusive contacts, but small, irregular branching, minor dykes sometimes occur as offshoots of larger dykes. There is a roughly north-west to south-east trending basalt dyke, more or less bisecting Cousine.
Ridge and groove weathering of granite rillenstein.
Tropical Island Recovery: Cousine Island, Seychelles.1st edition. By Michael Samways, Peter Hitchins, Orty Bourquin, and Jock Henwood. Published 2010 by Blackwell Publishing Ltd.
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Limestone intrusion (mauvish, in centre), wedged between pink granite in the cave on the north side of Cousine. The white area in the bottom left is recent coral rubble washed into the cave.
The exposed north facing cliff of the North hill.
The granite, where it slopes directly into the sea, presents a rough boulder coastline, usually with moderately steep to precipitous slopes. Bare boulder surfaces are prominent on the ridge, the south-west facing slopes, and on the north-facing hill slope, some as backbone-like projections, and others as small cliffs.
Cave at sea level, on the north side of Cousine, with a tide-caused drift-line of Sargassum seaweed, shell and coral remains. The cave is very hot and humid, and contains life in the form of algae, crickets, woodlice and the Island whip scorpion.
A range of diverse habitats on the South ridge. The granite slabs and boulders form the bases of a range of habitats from bare, exposed rock shelves and faces forming small cliffs, to overhangs and small caves. The crevices between boulders are often filled partially or completely with soil. This is formed of weathered granite, wind blown sand and detritus particles, as well as of the accumulated debris of plants and animals, and in particular, the faeces of giant millipedes. It forms a red earth with a blackish organic top-soil. In some areas, the boulders are completely covered by soil, but the only deep soils are those in deep crevices. Vegetation protects the soils by giving shade, and providing shelter from wind. It also keeps the soil moist. These provide further habitats for plants and animals which otherwise may be unable to survive exposure to sun and wind.
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The sandstone Overlying the granite on the north and east coasts is a sheet of phosphate-cemented sandstone associated with guano deposits, probably formed in the last 6 000 years. The phosphatic sandstones indicate the presence, over a long period of time, of large colonies of seabirds on the Island. Behind the dune crest is a narrow belt of Shioya soil. On the plain it is primarily Jemo soil, a fertile organic layer overlying the sandstone, also indicating that large seabird colonies were present in the past. Today this layer is reduced as a result of agricultural exploitation in the past. However, with the current restoration programme, this layer is re-establishing with a concurrent increase in invertebrate species richness and abundance. Hydromorphic soils occur in a drainage line along a portion of the south-western edge of the sandstone.
The sandstone underlying the beach, and sometimes exposed in places with a change of wind and tide, is rich with sea-shell and coral fragments, while those on the plain are finer-grained and have far fewer inclusions. On the north-east plain, seasand underlies the sandstone layer, and is about 2 m deep. The sandstone sheets appear to be variously sloped and fractured in places. These slopes and disruptions are probably caused by the underlying granite and old beach contours. The sandstone forms the base on which the beaches, dunes and coastal plain is formed. Exposed sandstone on the plateau with pockets of soil accumulating in shallow depressions.
The beach sand has been removed by the action of very strong North West Monsoon wave action, exposing the underlying phosphate-cemented sandstone.
Vertical soil profile showing the thin layer of blackgrey organic topsoil, overlying lateritic sandy deposits, which in turn overly phosphate-cemented limestone.
The sandstone is rich in ancient sea shell fragments.. (see . next page)
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The sand The sand is derived from broken down coral, seashells, marine and terrestrial rocks, remains of calcareous exoskeletons and wind-blown particles. It is carried by wind and water onto the sandstone and granite where it forms beaches and dunes. On Cousine, the Trades and the Monsoons have an enormous influence on beach characteristics and formation. During the Trades, sand from the eastern beach is removed and transported away, while there is accumulation of sand and widening of the north beach. The process is reversed during the Monsoons. During any year, beach widths may vary from 123 m wide to being completely washed away.
...and in ancient sea-shell coral fragments.
Beach changes through a full seasonal cycle.
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The beaches are most stable from the end of the Trades to the beginning of the Monsoon (October to December). By measuring beach widths monthly at 30 m intervals, and estimating mean beach sand depths, approximate beach sand volumes could be calculated. These ranged from a total of 70 980 m3 at the end of the Trades to 108 720 m3 at the end of the Monsoons. Indications are that sand is not simply redistributed on the beaches from one part to another, but is also being brought ashore from marine deposits during the Monsoons, and removed from the beach during the Trades. In recent years, there has been some erosion of the beach crest, which occurs when wind pushes behind spring tides. This is the result of global climate change and rising sea level, which is predicted to increase in the Seychelles by 0.23-0.69 m by the year 2100 (Gerlach 2008b). There are indications that precipitation, air temperature and sea-surface temperatures are also gradually increasing, with longer dry spells and more intense precipitation events predicted for the future (Payet and Agricole 2006).
The North West Monsoon in the process of eroding the northern beaches.
The beach crest on the north side of the island undergoing erosion with the surge behind the spring tide on 7 December 1995.
The beach crest shape changes rapidly, from gently sloping to vertical, depending on the prevailing winds and currents. Beach sand losses of 540 m³ over a 30 m section of beach over 24 hours have been recorded.
Possibly the first signs of rising sea level effects as a result of global climate change. High spring tide, coupled with moderately strong winds, are seen here making inroads into the dune crest in April 2007.
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The changing of sand volumes by erosion and deposition changes the beach profile. Even though the beach crest and the beach are unstable, most dunes remain unchanged. Stability of the dune system can be shown by the presence of vegetation, especially large trees, which give an idea of how long the system has remained stable. For some of Cousine's dunes, this has been for over 30 years, and probably much longer. Nevertheless, during some turbulent years and high tides there can be erosion of the dunes, and apparently increasingly so in recent years.
The final effects of the annual erosion process as the Monsoon diminishes There is thus the same burying and denuding of substrates in the sea as on land, with similar consequences for habitat change. The greatest volume of sand at the end of the Monsoons is on the East beach, while during the Trades, the largest volume is on the North beach. It is not unusual to find pieces of light grey volcanic pumice on the beaches of Cousine. This rock type is so light, from many little air pockets, that it can float on the sea for months. It is not known where this pumice comes from, but in all likelihood it is from volcanic eruptions in Indonesia.
Total beach sand volumes of East beach in relation to wind conditions and turtle breeding (extent of breeding seasons indicated by red arrows).
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Dune crest erosion from increased sea surges was already evident in November 1997,as seen by this fallen Casuarina tree.
East beach: May
Half-flower shrubland undermined by the prevailing sea conditions in September 2000.
East beach: August
The unstable beach crests can vary in height from being almost indistinguishable to 2 m high. A stable dune can be less than 0.5 m high to over 4 m high. Beach crests and dunes can have faces, which are determined by the prevailing sea conditions, varying from gently sloping to almost vertical. EAST BEACH SHOWING EFFECTS OF BOTH MONSOONS AND TRADES FROM JANUARY TO SEPTEMBER
East beach: September
East beach: January
East beach: April
End of East beach showing high eroded dune face with collapsed Casuarina trees, probably 30-50 years old, indicating the instability of the dune face. Recolonisation of the eroded face is taking place by Coast-grass, Beach morning glory and a small amount of Spikeweed. (Since this picture was taken, in 1995, the Casuarina trees have been removed).
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There has been extensive undermining of the dune face, especially where the Casuarinas occurred on the south beach, and, to a lesser extent on the north beach. This has resulted in sand loss with the casuarinas being uprooted and collapsing onto the beach.
Below are the dune profiles in schematic form of the south, east and north beaches, with the Casuarinas as the dune crest vegetation:
DYNAMICS OF THE COUSINE ISLAND DUNES
The section of the dune on the south beach has undergone considerable erosion by the sea. This is mainly due to undermining during the SE Trades.
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THE MOODY SEA General characteristics The sea within a kilometer of Cousine's shore is no deeper than 30 m, and the underwater visibility is generally very good, with exceptionally clear water during calm periods. During the Trades, the sea surface temperatures in the Seychelles have a minimum of 2327°C and a maximum of 28-31°C at different times of the year. Average ocean salinities are about 3.5 g of dissolved salts in 100 g solution, generally expressed as 35 parts per 1 000 (3.5%) and salinities of ocean surface waters can change depending on rainfall and evaporation. During the Trades, the salinity around Cousine is 34.3-35.2 parts per thousand.
The main oceanic current in the Seychelles region is the south equatorial current, which moves from east to west, with its main flow between 8 and 14 degrees latitude south. The granitic Seychelles lie on the northern edge of this current. It is unlikely that this current, which is one of the very long wavelength waves circulating around the oceans, has a great deal of influence on the local water movement around Cousine.
Wind and currents interact on Cousine's North beach to produce converging wave patterns.
Aerial view of Cousine in 2007 showing the shore characteristics and the fringing reef on the eastern side. Warm water with intermediate salinity conditions is characterized by a maximum abundance of herbivorous copepods, and a great diversity of krill (small crustaceans). These small, shrimp-like crustaceans often form huge shoals, and are an important food for fish, whales and other predators. Understandably, such waters support an abundance of some fish species, including flying fish. The continued high densities of these animals are an important factor for maintaining a variety of predators. Abnormal oceanographic conditions can reduce the numbers of the small crustaceans, which, in turn, results in lesser fish numbers. Seabirds in particular, can be severely affected by such a food shortage, which often results in delays at the beginning of the breeding season and increased mortalities.
The regular tidal range around Cousine is only 1-2 m between successive high and low spring tides (occurring at full and new moon). In turn, the main factors influencing water movement and wave action are the wind speed, direction and water depth. Patterns of wave refraction, current and eddy formation strongly affect the near-shore benthic communities. These patterns cause accumulations of Sargassum seaweed which are torn off their rock and pavement bases by wave action. Distribution of such loose material, including sand and rubble, indicate wave and current strength and direction.
Sargassum washed on to the shore after a storm.
Tropical Island Recovery: Cousine Island, Seychelles.1st edition. By Michael Samways, Peter Hitchins, Orty Bourquin, and Jock Henwood. Published 2010 by Blackwell Publishing Ltd.
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CONTENTS Seabed characteristics The seabed characteristics around Cousine have to be seen against the great Western Indian Ocean bleaching event of 1998. During the first half of that year, sea temperatures in the Western Indian Ocean soared. They were being measured at the time off the eastern shore of Cousine during the January and February, with the average temperature being 32ºC at 3 m below the surface. These warm temperatures caused many hard corals to expel their microalgae symbionts, known as zooxanthellae, resulting in the coral dying, and the reef breaking down in many areas. Coral reef dieback in the Seychelles was severe, with over 90% loss of the reefs in places (Sheppard et al. 2005; Graham et al. 2006), including Cousine, and a simplification of the texture of the seabed (Collier and Humber 2007). While the Eastern reef was reduced to rubble maintaining some structure, the Western reef was so severely broken down that today there is little sign that coral reefs ever existed. The coral reef is composed of many different hard coral species and a whole host of other fauna which also became depleted when the fringing reef was effectively lost. Interestingly, there was considerable difference in susceptibility to bleaching by the various coral species (Samways and Hatton 2001; Floros et al. 2004). The first to show bleaching were the Acropora species, especially A. clathrata, which was one of the first to show signs of dieback yet also one of the first to re-establish on the granite boulders in subsequent years. Such a severe bleaching event must have been a rare occurrence in the past, as one large colony of Diploastrea heliopora, which was estimated to be well over 1000 years old, succumbed during the exceptionally warm months. The species has not been seen since on Cousine. However, some coral species were very tolerant of the high sea temperatures, especially Pavona clavus and Porites species.
Acropora clathrata on the reef slope in February 1998, and beginning to show signs of severe bleaching.
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Acropora formosa on the reef slope in February 1998, showing stress from bleaching and rapid overgrowth by brown algae.
A section of the reef front with a healthy stand of the staghorn coral Acropora formosa in January 1998, just at the onset of the great coral bleaching event in the Western Indian Ocean.
The same section of the reef front in April 2007 with the remains of the staghorn coral packing down on the seabed to form cemented rubble.
The southern, western and north-western near-shore sea bed is comprised mainly of granite boulders, coral rubble and sand. The granite boulders generally are densely packed towards the shoreline, becoming scattered in a sand and rubble matrix farther away from the Island. They are colonized by hard corals, such as Pocillopora eydouxi and Acropora clathrata, accompanied by zooanthids and soft corals, Sargassum and encrusting algae. Substrates protected from wave surge by these boulders show a higher proportional cover of coral than adjacent areas. Although there is extensive stable substrate, which is elevated above the influence of abrading, surge-driven sand, the granite, prior to 1998, supported less than 20% live cover of hard corals, a situation general in the Seychelles. These granite rocks are important source habitats of corals which, no doubt, over future years, even decades or centuries, will seed the sandstone beds which formerly supported the fringing reef.
Tops of granite rocks colonized by hard coral, such as Pocillopora eydouxi, and elevated above the abrading surge-driven sand. This mature colony was photographed prior to the great bleaching event. These granite rocks area nursery for newly-established coral colonies after the great bleaching event of 1998.
Young coral stands on granitic rocks nine years after the great bleaching event. These rocks will probably seed the sandstone in future years, enabling the reef to recover.
A young colony of Acropora clathrata on a granite boulder nine years after the great bleaching event. Although one of the first species to succumb to the impact of high sea temperatures, it is also one of the first to show vigorous recovery. The area of confluence between the currents flowing east and west past the island and meeting at the northeast point separates two communities. West of this point, Sargassum with foliage cover of 100%, occurs over large areas. Corals, other than a few massive Porites, are restricted to the tops of rubble banks. East of the confluence, the foliage cover of Sargassum did not exceed 30% prior to 1998, but has reached 80% since then.
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The very turbulent north-east point with almost total Sargassum cover.
There are three main types of reefs in the Seychelles: fringing reefs, platform reefs and atolls. Fringing reefs are characteristic of the granitic islands such as Cousine, but vary greatly in their degree of development. Because of the shallowness of the Seychelles Bank, the fringing reefs have reef fronts up to only about 20 m high. Cousine Island, prior to the bleaching, had a fringing reef along its eastern and northern sides, whose total area was larger than the Island's surface area. Today this area is largely platform limestone, overlain by fused coral rubble, with occasional granite boulders and patches of sand. This area has been extensively colonized by a carpet of an orange soft coral of unknown identity.
Sea bed of granite, sand and rubble on the southern and western sides of the Island. A soft coral which has colonized the coral rubble beds since the great bleaching event of 1998.
Fused coral rubble overlying the limestone platform on the east coast.
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Fringing reefs have a number of different physical elements which are partly determined by southern ocean swells and a northerly tidal stream. On Cousine, for example, the reef area is dominated by mobile banks of rubble derived from storm-damaged and bleached coral, and by sand/rubble flats colonized by several species of Sargassum and xeniid soft coral. It appears as though rough weather occurs with sufficient frequency to inhibit recolonization by corals. In the absence of hard corals, pioneering species such as soft corals and large algae predominate. Since the great bleaching event, certain hard corals have begun to establish again, which may eventually lead to the reformation of the fringing reef.
Part of a fringing reef, prior to the great bleaching event of 1998, with a hard coral in the centre and a soft coral below and to the right.
The same Porites solida massive in 2007. The surrounding Pocillopora colonies have disappeared and the coral surface has become more textured since the great bleaching event of 1998.
The fringing reef is dotted here and there with the massive coral Porites solida and an extensive bed of Pavona clavus. These two species were remarkably resilient to the great bleaching event and continue to survive today almost as sentinels in an otherwise desolate landscape of coral rubble.
A large colony of Pavona clavus in 2007, and which survived the great bleaching event.
A massive coral, Porites solida(on the right) forming a large mound on the seabed. On the left is a colony of the coral Pocillopora eydouxi in which is sheltering the endemic Seychelles squirrelfish. This picture was taken prior to the great bleaching event. These Fungia sp. mushroom corals rapidly succumbed to the great bleaching event, but as shown here, also rapidly recolonized the reef front by 2007.
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CONTENTS The surf zone This is a shifting margin characterized by high energetics. The sand is loose and mixed with abraded and mobile coral fragments contributing calcareous elements to the sand, and giving it its white colour.
Calcareous red algae dominating one section of a granite boulder in the high-energy surf zone.
The sea bed in the surf zone is made up of sand which is white in colour from continually abrading mobile coral fragments Prior to the great bleaching event, this zone had some hard corals, which were exposed at low tide. Because of the high energy wave action, these had developed into short, robust forms in comparison with the colonies of the same species in stiller water.
While the seabed in the surf zone has changed from one with frequent patches of hard coral, such as Acropora formosa and A. robusta, before the great bleaching event, it now has patches of filamentous red algae. Despite these changes in seabed, there is no evidence that the surface water fauna has changed, as elsewhere in the Seychelles (Sheppard et al. 2005), possibly because the reef was so small.
The surf zone on the granite rocks is today dominated by brown Padina, as well as Sargassum, and by various red algae, including encrusting types.
The very high-energy surf zone provides opportunities for those species, such as this Pompano, to forage on the incoming tide. The seabed is dominated by red algae, whereas prior to the great bleaching event, there was hard coral at this site. Padina brown alga on a small granite boulder in the surf zone.
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The intertidal zone The intertidal zone is the area between high and low tides, which varies in height above sea-level from 0-2 m. On Cousine, the intertidal zone sections in which granite boulders occur, occupy about 1.8 km (67%) of the Island's 2.7 km coastline. Except when sandstone pavement is exposed at low tide, the rest of the intertidal zone is beach sand. Changes in wind speed and direction, and consequently, current and wave action, can cause boulders, pavement and rubble to become partially or wholly covered by sand within a few days. The characteristic of the intertidal zone is change: daily, weekly, monthly and annually. The animals and plants of the intertidal zone, especially in areas affected by sand movements, have a precarious life, and have evolved adaptations or behavioural patterns to cater for the change in environment from aquatic at high tide, to semi-terrestrial or terrestrial at low tide.
Sargassum driftline on the North Beach, with large amounts still floating in the sea.
Intertidal area indicated by rough rocks with their covering of mainly algae and molluscs.
Prior to the great bleaching event green algae such as this, Chlorodesmis were commonly seen among hard corals in the surf zone. Today, it is more restricted to isolated areas of rock where it is in competition with red algae.
A distinctive feature on the east beach of Cousine is the formation of a beach pool/lagoon following the onset of the Monsoons. It is generated by the deposition of beach sand in a wide tongue which isolates the central part of the sandstone reef. At isolation, this entrapped body of water varies from 200-300 m in length, 30-50 m at its widest point, and up to 2 m deep. Organisms become trapped in this beach pool, including seaweeds, crabs, prawns, sea hares, sea-cucumbers and fish, mainly Milkfish (Chanos chanos). The pool decreases in size by deposition of beach sand for the duration of the Monsoon, but nevertheless can last for up to five months before finally silting and drying up. In that time, a number of the trapped organisms die, due to temperature rises and de-oxygenation of water by rotting seaweed. Shallow water (3 cm deep) at the edge of the beach pool can reach temperatures of 38ºC, but the deeper water (60 cm or more) is usually at or only slightly higher than the sea surface temperature. During spring tides, new seawater enters the temporary system, refreshing it.
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CONTENTS
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COUSINE'S GREEN CARPET
The terrestrial vegetation of Cousine Island is more similar to the outer coralline islands than to the high granitic islands. Among the shared species are Pisonia (Pisonia grandis), Fleshy portulaca (Portulaca oleracea), Coastg r a s s ( S p o ro b o l u s v i rg i n i c u s ) , C o m b g r a s s (Dactyloctenium ctenoides ) and Fine steno (Stenotaphrum micranthum). This similiarity with the coralline islands is also shared with other low granitic islands (e.g. Frégate, Aride, Recif and Cousin) and many smaller peninsulas and promontories of Mahé, Praslin and Silhouette. Plants such as Half-flower (Scaevola sericea), Coast cordia (Cordia subcordata), Rosewood (Thespesia populnea), Alexandrian laurel (Calophyllum inophyllum), Sea hibiscus (Hibiscus tiliaceus), Beach morning glory (Ipomoea pescaprae), Fireleaf (Euphorbia pyrifolia), and Seychelles enteropogon (Enteropogon seychellensis) are virtually confined to these areas. Pisonia occurs in communities on seven other small granitic islands. The species is an important habitat for birds such as the endemic Seychelles magpie robin, the Seychelles warbler, and for tree-nesting seabirds. Although the tree occurs throughout the tropical IndoPacific region, its existence as a forest dominant is very rare (Gerlach 2008a). Another tree of importance is the endemic Balfour's pandanus (Pandanus balfourii), which forms a community on the west side of the Island, with patches scattered in other parts. Like Pisonia, this tree provides many roosting and nesting sites for mainly seabirds, and by way of a thick leaf litter layer, is home to a rich invertebrate fauna. Cousine's main forests are dominated by figs (Ficus spp.), as well as Pisonia. They are classified as broadleafed and evergreen. Tree-root structures vary considerably, with figs for example often having an extensive adventitious root system, and Balfour's pandanus with stilt roots. The forest trees' foliage can start from near the bases to about halfway up the trunks, and the leaves are generally simple and large, each of which can have a leaf surface area of over 4 500 mm². The canopies range from 5 m to 20 m above the ground, and are continuous or virtually so. Emergent Coconut trees tower above the fig tree canopy on the hill slopes, which is not a natural condition. There are no lianas or epiphytes in the forest. Climbers are occasional, with one species, the Five-leaf morning glory (Ipomoea venosa), being widespread. Ground cover varies considerably in density, and consists mainly of the Island fern (Nephrolepis biserrata).
Adventitious roots of Ficus lutea.
Adventitious roots of Ficus reflexa penetrating the spaces between the granite rocks.
Tropical Island Recovery: Cousine Island, Seychelles.1st edition. By Michael Samways, Peter Hitchins, Orty Bourquin, and Jock Henwood. Published 2010 by Blackwell Publishing Ltd.
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The occurrence of the Swamp fern in granite crevices along the south-west coast is of interest since it normally occupies wet areas in shade or semi shade, and there are no permanently wet surface soils where it grows on the Island. The presence of the fern can indicate underground water seeping out between the granite boulders.
Island fern is an important groundcover plant in the forest. The coastal plain of Cousine was highly disturbed in the past, having been used for various types of agriculture, such as Coconut (Cocos nucifera) and Casuarina (Casuarina equisetifolia) plantations, fruit tree stands, vegetable gardens, tobacco and cotton fields, and cattle grazing. It is uncertain what the original vegetation types were in these areas. However, the remnants of Pisonia forest in the north indicate that this forest type probably occupied all the coastal plains, as it still does on Cousine's sister-island, Cousin. Other open or semi-open areas occur as either disturbed areas, characterized by plants such as Beach morning glory and Coromandel (Asystasia gangetica), or by natural grasslands, especially Coast grass.
Plant pioneers and colonizers Plant pioneers are those which grow first on bare ground, while colonizers are those plants which grow into bare areas from areas outside these places. Colonizers of granite, where soil or debris have been caught in crevices or small hollows, include S e y c h e l l e s e n t e r o p o g o n ( E n t e ro p o g o n seychellensis), Swamp fern (Acrostichum aureum), Island fern (N. biserrata), White-headed sedge (Mariscus dubius), Indian mulberry (Morinda citrifolia), Fireleaf (Euphorbia pyrifolia), and Figs (Ficus spp.).
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Island fern as a pioneer among granite boulders in full sun on a north-facing slope. The unstable beach sands and dunes can be rapidly covered by the Beach morning glory, a coloniser par excellence with its remarkable powers of growth. This creeping plant is capable of sending its long, probing shoots over the bare sand at the rate of 1 cm per hour - a veritable speedster of the plant world. Plant colonisers like the morning glory modify harsh environments by providing shade and litter, and enable other plants to grow in these areas. The sea eroding its sand base is about the only force that stops it in its tracks.
Cultivated communities
The creeping Beach morning glory on shallow soils and bare rock.
Colonization by Beach morning glory on beaches is halted as tides impact on the beach.
Mown and cultivated communities Mown lawns These are defined as herbaceous communities that are cut at regular intervals around buildings to sward heights of less than 5 cm. The sward varies in species composition depending on the moisture, degree of shade, soil depth and frequency of mowing. Prior to 1995 the dominant lawn grass was Star grass (Cynodon dactylon). After that date, Broad-leaf steno (Stenotaphrum dimidiatum) has been the dominant species, with other components being Star grass, Little sticky seed (Boerhavia repens), Prostrate euphorbia (Euphorbia prostrata), and a number of sedges.
The cultivated communities cover a well-defined area of 0.3 ha, and consist mainly of non-invasive introduced plants which supply food for the Island's inhabitants. While large, woody fruit trees remain permanent, the herbaceous plants are ephemeral, and are replaced at intervals by the same, or other, species. The ground cover, where it does not consist of food plants, is either bare ground or cut lawn, except along edges of the area, where numerous herbaceous plants occur. A Banana (Musa sapientum) plantation with a semiclosed canopy 3 to 4 m tall is established on the rich soils of the drainage line. Three kinds of banana occur, one bearing a small thin-skinned fruit, another the large, angular fruits used for cooking rather than being eaten raw, and a red-skinned fruit of good eating quality. The other food plants include citrus (Citrus spp.), Mango (Mangifera indica), Avocado (Persea americana), Papaya (Carica papaya), Otaheite gooseberry (Phyllanthus acidus), Soursop (Annona muricata), Custard apple (Annona squamosa), Breadfruit (Artocarpus altilis), and a host of vegetables, which vary from time to time. Naturalised herbs such as Short-fruit and Long-fruit phyllanthus (Phyllanthus amarus and P. tenellus), as well as patches of Vernonia (Vernonia cinerea) occur in the disturbed edges of this area. Papaya seeds are readily dispersed by the tortoises and fodies, resulting in occasional establishment of these alien plants among natural vegetation, and require monitoring and continual control.
These giant tortoises are important dispersers of certain seeds.
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Coast grassland on the south west coast.
Papaya escapee (centre of picture) in the coastal forest.
Grasslands Coast grassland This natural grassland is dominated by Coast grass (Sporobolus virginicus), which forms dense swards to 30 cm tall. Where the sward is less dense, particularly on the edges, other plants occur, such Spikeweed (Achyranthes aspera), Madagascar periwinkle (Catharanthus roseus), Comb grass (Dactyloctenium ctenoides), Broad-leaf steno (Stenotaphrum dimidiatum), Little sticky-seed (Boerhavia repens), Blue-green sedge (Mariscus ligularis), Fleshy portulaca (Portulaca oleracea) and Beach morning glory (Ipomoea pescaprae). Wild grenadilla (Passiflora foetida), Pigweed (Amaranthus dubius) are alien plants that are continually controlled for eventual eradication. Poison apple (Datura metel) has now been eradicated. On the east coast, the grassland is more or less confined to the dune crest. Most of the mature Casuarina trees used to occur in this grassland, but have now been eradicated.
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Invasive Wild passion fruit occurs on the edges of the Coast grassland.
Very small patches of grassland occur along the edge of the granite on the south-west coast, the largest area being in the south. On the south-facing slopes, the grass cover is generally pure, except along the edges of the community, where trees such as figs and Indian mulberry have established, usually behind sheltering rocks, out of the direct salt spray. During windy conditions, the grass is often wet with salt spray.
The debilitating effect of salt spray on Pisonia, Broadleaf steno, Beach morning glory and Pandanus palms on the exposed north west coast.
Jamaican vervaine.
Coast grassland in the foreground with Comb grassland developing just above it on the left side, on west facing slope, north west coast.
Steno grassland Although Broad-leaf steno (Stenotaphrum dimidiatum) usually occurs as a component of other communities, it can form dense stands. A belt of this grass, 70-75 cm tall, occurs in a trough behind the dune crest of the north beach. Some Madagascar periwinkle, Jamaican vervaine (Stachytarpheta jamaicensis), Fireleaf, Seychelles phyllanthus (Phyllanthus pervilleanus), Comb grass, Spikeweed, and Large-leaf morning glory (Ipomoea macrantha) are present in this grassland.
Large-leaf morning glory.
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Herblands Morning glory herbland The herbland is open and dominated (over 50% leaf cover) by the rapidly growing Beach morning glory. Madagascar periwinkle is also common in patches, which vary in size. Another plant found in this herbland and occasional sunny spots in the fig forest is Five-leaf morning glory (Ipomoea venosa). The largest community is in the north, where it grows to 4080 cm in height, and scrambles over boulders, sometimes covering these entirely. Other plants in the community include Spikeweed, Coromandel, Comb grass, Seychelles enteropogon, Fleshy portulaca, and Coast grass.
Beach morning glory is so dominant that it covers over half the open herbland. Madagascar periwinkle can be a dominant herb and form a carpet in the full sunlight. This species has now been largely removed as part of the island restoration strategy.
Five-leaf morning glory, in its typical habitat among boulders.
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Fleshy portulaca is interspersed in the Morning
glory herbland.
Morning glory– Coast grass herbland This is a herbland in which Beach morning glory coexists with Coast grass, each contributing about half the leaf cover. The community is secondary, and restricted to one area, probably reflecting the results of former grazing by cattle. It appears that Coast grass becomes dominated by Beach morning glory in areas where there is less soil among the granite boulders.
Mixed herbland on the coastal plain behind the beach dune in 1995. The dominant plants are Coromandel and Beach morning glory. This herbland had, by 2008, been removed and replaced with grass and indigenous trees. Cousin Island is in the background.
The former Coromandel herbland, North point in1996. This has now been restored to grassland.
Morning glory – Coast grass herbland, North point.
Coromandel herbland This herbland was formerly dominated (over 80% leaf cover) by Coromandel (Asytasia gangetica), an introduced soft-leafed herb. It is 55-75 cm in height, and up to 1.8 m high when scandent on boulders. Grasses such as Seychelles enteropogon, and Finger grasses (Digitaria spp.) also occur here. Beach morning glory and Spikeweed are frequent edge components. As part of the island restoration plan, this herbland has now been largely removed, mostly in favour of grassland to encourage Sooty tern nesting.
The former herbland.
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COUSINE'S WOODY CLOAK
Shrublands Hibiscus stands Hibiscus shrubland is one dominated entirely by Sea hibiscus (Hibiscus tiliaceus). There were originally two small, natural stands, 4-5 m in height, and forming much-branched thickets. With the rehabilitation programme their distribution on the island has been increased.
A developing Hibiscus stand in 2007; formerly a Casuarina forest. Replanted on the dune crest in 2001.
Half-flower stands Half-flower stands are dominated by the Half-flower (Scaevola sericea). Prior to restoration, these areas were not common or extensive on Cousine, although today it is a common plant as many plants have been established on the dunes as part of the Island's replanting programme. It also occurs on granite, although generally favouring coastal dunes. A patch of about 60 m2 occurs in the Saddle area, where it appears to be dying out, and is being encroached by Pisonia.
The flower and fruit of the Sea hibiscus.
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The aptly named the Half flower (flowers above and fruit below), which has been established as part of the restoration programme on the dune crest.
Tropical Island Recovery: Cousine Island, Seychelles.1st edition. By Michael Samways, Peter Hitchins, Orty Bourquin, and Jock Henwood. Published 2010 by Blackwell Publishing Ltd.
A variety of sedges occur on the plain, from the large (up to 1.2 m tall) tufted Blue-green sedge, with its dark brown flowering heads, to the smaller common Whitehead sedge, Compressed sedge (Cyperus compressus), Spiky sedge (C. conglomeratus), Roundhead sedge (Fimbristylis cymosa), Greenhead sedge (Kyllinga polyphylla) and, near the granitic boulder interface, Feathery sedge (Pycreus polystachyos). Although usually flowering at about 50 cm in height, the Compressed sedge and Spiky sedge can flower when under 10 cm high and frequently cut, as in lawns and tracks. Restored Half-flower stands along the dune crest.
Secondary herblands/woodlands The secondary herbland/woodland community is an open (formerly forest) herbland and grassland, with scattered woody plants with no characteristic dominants. The density of plants (woody and semi-woody species) can reach 2 670 per ha, with a canopy height of 2-10 m. The canopy covers less than 15% of the area, and which continues to diminish as the planted trees continue to grow. Grasses include small patches of Comb grass, Coast grass, Star grass, Long-spike lepturus (Lepturus repens), Shortspike lepturus (L. radicans), Brachiaria (Brachiaria subquadripara), scattered tufts of Seychelles enteropogon and Love grass (Eragrostis tenella), Finger grasses and Foxtail (Pennisetum polystachyon).
Brachiaria lawn is grazed by the Giant tortoise, in some areas leading to dense, short swards.
Whitehead sedge.
Blue-green sedge.
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There is still uncertainty as to which herbs are indigenous, and which are introduced. Many of the species are widespread in the tropics. The plain is occupied by numbers of these plants, of which the most prominent is the Madagascar periwinkle, with its dark green leaves and pink or white flowers. Other herbs include Little sticky-seed, Pigweed, Fleshy portulaca, Yellow alder (Turnera angustifolia), Indian acalypha (Acalypha indica), Hairy euphorbia (Euphorbia hirta), Prostrate euphorbia (E. prostrata), Poison apple, Jamaican vervaine (Stachytarpheta jamaicensis), and Coromandel, Hairy euphorbia, Prostrate euphorbia and Little sticky-seed, and all are colonizers of bare ground.
Prostrate euphorbia, a colonizer of bare ground. The Little sticky-seed is particularly interesting as it belongs to the same family, Nyctaginaceae, as does Pisonia. Both these plants have hooked, sticky seeds which, when clumped on bird feathers, immobilize the birds. Cases of total entrapment by Pisonia are fairly common, but by the Little sticky-seed is much rarer.
Little sticky-seed, leaves,and flowers, which can occasionally entrap small, indigenous birds. Little sticky-seed.
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A male Madagascar fody having perished after being entrapped by the seeds of Little sticky-seed. Taller herbs with woody stems are Rhombic triumfetta (Triumfetta rhomboidea), Indian abutilon (Abutilon indicum), Stinkweed (Senna occidentalis), and Sesbania (Sesbania sericea). Climbers and creepers are common in some areas, particularly the Large-leaf morning glory, which forms green ground mats and covers small shrubs and trees in a north-east section of the plain. The Wild bean (Canavalia cathartica) occurs in shaded areas, more commonly at the edge of the plain and granite. A commercial species which was deliberately introduced in the past, and which has been eradicated is Cotton (Gossypium hirsutum). It used to form a broken belt along the north east section of the plain. The white fibres surrounding the seeds were used by birds, such as the Seychelles sunbird, Seychelles white-eye and the Seychelles warbler, to make or line nests.
Cotton ball breaking open, releasing fibres which were formerly used by the endemic Seychelles sunbird and Seychelles warbler as nesting material.
Naturally occurring, woody species include scattered individuals of Indian mulberry, Seychelles phyllanthus (Phyllanthus pervilleanus), Fireleaf and Sourplum (Ximenia americana). Sourplum occurs in a narrow belt on the edge of the interface between dune and plain. It is very scarce in the granitic Seychelles. The small population on Cousine is a healthy, growing one which flowers and fruits regularly. It is being retained on the Island although it is uncertain whether it is in fact indigenous to the Seychelles.
Sourplum in fruit. It is uncertain whether this species is indigenous to Cousine, but as it is not invasive, it is being retained on the Island. The secondary herbland-woodland has undergone rapid change to a woodland-forest community following the extensive planting of indigenous trees.
Woodlands and forests Fig-Euphorbia woodland Fig-Euphorbia woodland is an open community, with less than 40% canopy, and with Small-leaf fig (Ficus reflexa) and Fireleaf being the most common trees.
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Fig / Euphorbia woodland on the north slope of the North hill, and with Island fern in the shaded areas The community occurs mainly on the northerly steep, dry slopes. Ground cover varies from bare rock to patches of Fine steno, small patches of Blue-green sedge, Compressed sedge, and Whitehead sedge, especially in rock hollows, as well as some stands of Guinea grass (Panicum maximum) and Coromondel. On lower slopes, and in more shaded areas, Forest panicum (P. brevifolium) occurs. Island fern is common, but often as dry, dead patches.
Pacific almond forest This forest is characterised by a canopy dominated by Pacific almond (Terminalia catappa), which thrives on damp soil. On the edge of the sandstone plate and the granites of the cultivated area is a dark-soiled channel which was a small swamp area prior to it being drained and partially filled in the past. During rain, sections of this area become sodden, and at its southern end, a depression bordered by large granite boulders on its landward side, becomes filled with water. The area has been planted to Pacific almond, while other woody plants such as Coconut, Otaheite Gooseberry and Indian mulberry have also established. The lower section of the swamp passes through Indian mulberry and Pisonia forest.
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The drainage line and the developing Pacific almond forest in 1995 with remnants of the Swamp grass below the Coconut palm. At one stage, Swamp grass (Paspalidium geminatum) formed a dense, robust stand in an open section of the swamp. This grass is an indicator of water-formed soils (hydromorphic soils), and occurred only in this one area on the island. It was completely shaded out by restoring Pacific almond by 1999. Associated with the drainage line and its edges are Nightshade (Solanum americanum) and Sessile alternanthera (Alternanthera sessilis), both species preferring semi-shaded, damper, sheltered conditions. Previously cultivated Yam (Alocasia macrorrhiza) has been removed from under the Pacific almond canopy.
Fig forest This forest is a closed-canopy community in which Small-leaf fig (Ficus reflexa) and Large-leaf fig (F. lutea) make up at least 60% of the canopy. The forest is characteristically broad-leafed, partially evergreen, and has a closed-canopy height ranging from 7 to 20 m. Woody plant densities reach 1 480 plants per ha, with Coconut palm seedlings having relatively high densities in places in the under-storey. Ground cover is dominated by the Island fern (with a groundcover of 4-5%), while the climber Five-leaf morning-glory is occasional. No lianas or epiphytes are present. Bare rock comprises 20-22% of the ground surface, while litter is estimated to cover 75% of the soil between the exposed rock.
Fig forest.
Fig-Pisonia forest This forest has a virtually (98%) closed canopy, and is forest in which Pisonia and figs make up over 70% of the canopy. The community is a broad-leafed evergreen forest with canopy heights ranging from 7-20 m. Other canopy components are Indian mulberry, Fireleaf, Takamaka and Coconut palm. Woody plant densities range from about 1 330 to 2 960 per ha, with the canopy dominants having mean densities as follows:
Fireleaf Small-leaf fig Pisonia Indian mulberry Large-leaf fig
710 per ha 429 per ha 355 per ha 324 per ha 14 per ha
Fig-Pisonia forest with a windblown Fig tree in shallow soils in the foreground. Island fern is a common groundcover plant, with a cover up to 5%. Other plants are also occasionally present, especially near the community edges, most common being the climber, Five-leaf morning-glory. While Coconut palms do not contribute greatly to the canopy, their seedlings can occupy a major proportion of the ground cover, often forming dense aggregations under 2 m in height. These are regularly cleared, as they are an invasive component of the forest. Bare rock occupies about 30% of the ground surface, while litter is estimated to cover between 55% to 85% of the soil surface.
Pisonia forest This type of forest is one in which Pisonia provides more than 80% of the canopy. It is rare as an extensive community in Seychelles, and indeed, in the world (Gerlach 2008a). The best examples in the Seychelles occur on Cousin, Aride and Cousine. It is a very important tree, providing nesting sites, nesting material, copious leaf litter, and cool, damp conditions for a whole range of forest floor organisms.
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Edge of Pisonia forest with a fallen branch from strong winds, which provides the opportunity for vegetative growth.
Mature Pisonia forest. The Pisonia tree is very tolerant of a whole range of conditions, from deeper soils in damp areas to shallow, sandy soils in exposed areas. At the edges of undisturbed Pisonia communities, particularly on the southwest facing slopes, the canopy becomes lower and acts as a wind-protector. Some trees on the edges are less than 1.5 m in height. The boundaries between the Pisonia community and other communities are not always clear, particularly when figs and Fireleaf occur in areas where exposed rock dominates, and soil availability is restricted. The canopy height is from 6 m to 16 m, and is usually unbroken. Understorey plants are few, except where a temporary break in the canopy (e.g. a large fallen branch, or a wind blown tree) has taken place. Understory plants include Coconut, Five-leaf morning-glory and Island fern. Exposed rock covers about 25% of the ground, and the soil is 70% to 80% covered by litter. The total density of trees per ha is between 1 000 and 1 050 on granite, and about 2000 on the coastal plain.
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Regenerating fallen Pisonia tree.
The remnant Pisonia community on the coastal plain has a higher density of Pisonia trees, less exposed rock (about 4%) and more undercover species, including Coconut, Beach morning-glory, Wild bean, and Poison apple, than the Pisonia forest on granite. The Pisonia community has open edges, allowing penetration by neighbouring species. On the sandstone adjacent to the granite edges, Pisonia forest characteristics are similar to those of the community growing on granite. The Pisonia forest with its relatively complex architecture, is an important habitat for many forest organisms which seek shade and dampness. In turn, it provides an abundant food source, such as invertebrates living in the leaf litter, for some of the Island's rarest birds, including the Seychelles magpie robin. The Pisonia tree is ecologically important in other ways too (Burger 2005). It is an important roosting and nesting tree for sea birds, especially the Lesser noddy. As such, the tree encourages input of nutrients to the soil when the birds defaecate and drop pieces of food. Other organisms, such as skinks and the Dark ghost crab, also benefit from the extra dropped food items. The Pisonia tree is extraordinary in another way. The flower buds are a complex array known as a panicle. As the panicle matures into a chaotic ball of fruiting bodies it attracts ants which become stuck to the resinous sticky surface of the young fruits. This may be another way in which the Pisonia ensures it has sufficient nutrients. Yet the story does not end there. Even though sea birds are attracted to the tree for perching and nesting, each year many perish as they become entangled in the mature seed heads which are bristling with sticky spikes. White terns and noddies are particularly susceptible. It is thought that the hapless birds, on death, supply some essential nutrients to the tree's root system as the bird's body decays. In another respect, evidence suggests that the occasional death of a seabird by entanglement is the evolutionary price that the seabird species pay for a very sought-after nesting site. In turn, the tree appears to benefit by having its seeds dispersed to far away locations. While some birds die at the site of the mother tree, some of the seeds adhere to the birds, which cannot remove them all. These birds then disperse to other islands, giving the opportunity for the tree to establish elsewhere. While very few (only 0.1%) of the Pisonia seeds germinate under the parent canopy, they readily germinate in open conditions, which may be the case on occasions when the seed-laden birds arrive at their destination.
Similarly, although fallen seeds under Casuarina trees germinate, they rarely reach any size and die off or remain stunted. Why the Pisonia has such complex interactions with many other life forms, yet it is still so rare, despite its apparently complex survival strategy.
Pisonia seedlings having germinated, after the removal of alien weeds in 1995, under a Casuarina canopy in 1999. The Casuarina trees have since been removed.
The same plants in 2007 after the Casuarinas were removed in 2004.
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The complex flower head, or panicle, of the Pisonia tree.
Complete panicle. The mature panicle of the Pisonia tree forms a formidable trap for seabirds, especially Lesser noddies, whose flapping wings get caught among the spiked clubs
The flowers mature into green bunches (panicles) of sticky pods, which later turn brown as they age. Such a succession of panicles of different ages provides a long season during which various organisms become trapped. Close up of the sticky fruiting bodies (seed pods) of the Pisonia which can be a death trap for ants. Hooked fruit
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A Lesser noddy entangled in a Pisonia panicle.
A Lesser noddy totally entrapped in a Pisonia panicle and other debris picked up as it struggles in vain to release itself.
Tropic birds also occasionally become snared by Pisonia seeds.
Sometimes birds are lucky and manage to escape the entanglement of Pisonia seed.
Pandanus forest Pandanus forests are low and almost impenetrable in parts, with canopies of over 50% Balfour's pandanus (Pandanus balfouri), a plant with hard, serrated leaves.
While not often getting trapped, the White tern becomes easily immobilized with light loads of Pisonia seed.
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A typical Pandanus plant producing a substantial amount of leaf litter.
Pandanus forest on the southwestern slopes. The main forest lies in the north and northwest, with patches scattered along the south ridge. On north-facing slopes, Balfour's pandanus grows lower down the slope among large granite boulder outcrops. It provides the dominant crown cover and shading effect. The canopy is 92% closed, with Balfour's pandanus contributing 77% of the total. Other canopy species are Indian mulberry and Fireleaf, contributing about 10% and 5% respectively. Densities of plants over 3 m tall are about 2 300 per ha, with Balfour's Pandanus making up about 58%. High numbers (over 22 000 per ha) of Balfour's pandanus seedlings are present in some areas. Other species in these areas (especially on the lower slopes) include Coromandel, Spikeweed, Fireleaf, Indian mulberry, Small-leaf fig and Island fern, especially on rocky, open areas. The ground is littered with debris of dead Pandanus leaves, trunks and branches.
Pandanus buttress roots and the dense leaf litter layer.
Pandanus flower.
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Pandanus fruit and fallen leaves.
A view from Cousine's south ridge looking across to Aride, Cousin and Praslin Islands.
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COUSINE’S VEGETATION REPRIEVE Underlying philosophy and practical considerations During the 1960s, Cousine Island was highly degraded, and vegetation was sparse. It was, in Cairns' (2002) terminology, a dysfunctional relationship between humans and the environment. A decision was then made to undertake restoration (see definition: Society for Ecological Restoration International Science & Policy Working Group 2004) of the Island to re-instate its historic ecological integrity and ecosystem function. By the 1960s, it was clear that something had to be done on the Island, and soon, or else the island may well have undergone a catastrophic regime shift (Scheffer and Carpenter 2003), becoming highly depauperate, and not restorable to the 'original state' (see p. 2). Although in those early years, the Island had the appearance of being severely degraded (see p. 10), fortunately, it still retained much of its natural capital (sensu Esler et al. 2006; Aronson et al. 2007) for a restoration project to take place (Hobbs 2002). This remnant natural capital was retained as the topography and extremely rugged terrain left pockets of historical constituents, especially healthy soil, the essential foundation for restoration of biodiversity (Whisenant 2002). Such a healthy soil platform is, of course, essential for recovery of the plant community, the primary producers (Davy 2002). In short, there was extreme spatial heterogeneity of degradation, with exposed areas, especially the coastal plain, highly degraded, while these were interspersed with pockets of source habitats. These historical point sources were still rich in original biota, which made up the regenerative capacity for initiating restoration of the whole island. The one exception was the coastal plain, which had undergone a major regime shift, with largescale local extinction of indigenous species. This meant that the mitigation measures for this plain involved substantial establishment of primary forest plants. When setting the restoration goals, the philosophy as later outlined by Zedler (2007), was that the outcome was not simply about 'success' or not, but rather to redirect the ecological trajectory of the Island, away from heading beyond a transition threshold (sensu Hobbs 2002) where restoration was unlikely, to one where autogenic succession could then take its course (sensu Rolston 1994; Bradshaw 2002). In other words, the aim was to bring the Island to a point where the ecosystem's self-repair mechanisms could be 'jump started' (Whisenant 2002), and where sustainable resource fluxes were re-instated.
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Restoration is a multidimensional activity, yet also a manipulative one (Cairns 2002). On Cousine, the multidimensionality was characteristically about undertaking restoration on a small and highly sensitive tropical ecosystem without disturbing the wide range of very sensitive biota, especially the endemic plants, nesting seabirds and endemic land birds. As regards the plants, this meant avoiding use of herbicides when removing alien species, and also not disturbing the sea birds when they arrived to roost and nest. In turn, the level of most of the manipulation was at the trophic levels of the primary producers and vertebrate predators. There was no manipulation of the invertebrate community, which was left to its own devices to re-establish from the source habitats (remnant forest and grassland patches between rock outcrops) into the restored areas. Manipulation at the primary producer level was essentially two-fold: strategic removal of the alien plants, and at the same time, replanting indigenous plants after referencing what the 'orginal' or historic compositional and structural assemblage was likely to have been. Manipulation of the vertebrates involved removing alien grazers (domestic livestock), as well as eradicating alien predators (principally cats), and stopping poaching by humans. Although some first steps were taken in the 1970s to undertake recovery of the Island, the highly active and scientific phase of the restoration project began in 1995 and has continued ever since. Although this was essentially an ecological restoration project for the benefit of the indigenous, and much endemic, biodiversity, consideration was also given to cultural elements, following Davy and Perrow's (2002) point that restoration is a broader church than its scientific core. Inclusion of a cultural component faced some dilemmas, with not all facets of the overall restoration project necessarily in concordance with full restoration of ecological integrity and ecosystem function. One example was a small stand of highly competitive alien bamboo (Bambusa vulgaris), so widely used for many forms of basket work, including fish traps, which was temporarily left on the southern slope of the North hill to supply local fishermen, as well as building material for a school on Praslin. This was part of the overall 'pragmatic approach' (outlined by Bradshaw 2002) to restoration of cultural processes as an overlay to the ecological ones.
Tropical Island Recovery: Cousine Island, Seychelles.1st edition. By Michael Samways, Peter Hitchins, Orty Bourquin, and Jock Henwood. Published 2010 by Blackwell Publishing Ltd.
The coastal plain, north plain in 1995, prior to intensive restoration, and composed of mostly alien plants.
The northern corner of the north plain in 1995, prior to restoration, and with a dense cover of Spikeweed and Pigweed. There were seven inter-related phases to the restoration project: 1) assessment of the current ecological condition, and decisions made as to what the attributes of the restored Island ecosystem would be, 2) alien plant removal, 3) planting of indigenous species, both where aliens had been removed and where there were denuded patches, while also taking into account facilitation between plant species, 4) monitoring of the progress, 5) allowing of autogenic succession to take place, 6) planting of slower growing climax species, allowing for natural succession, and 7) continued monitoring. Alien plant removal and propagation of indigenous plants for establishment were run concurrently. Also, the restoration activities were area-specific as each part of the island required attention according to which alien plants were present and the intended restoration target, such as planting of a reference-based forest, or
Nevertheless, in all cases, the aim was to restore the historic ecological integrity and ecosystem health. Establishment of the various indigenous plants was also planned to mitigate towards the historic conditions of the Island, and to encourage population expansion and hence improved survival opportunity for indigenous animals. Most of these animals were already present on the island but were now being given more extensive habitat. This was especially so for forest-dwelling invertebrates and their endemic bird predators. Other animals were encouraged to return to the island of their own accord through suitable habitat provision. This was most notable in the case of the Sooty tern which returned to the Island after an absence of many years. Determination of the historic compositional and structural vegetation of the coastal plain presented challenges, as very few traces of the original vegetation remained. In response to this deficit of the ecosystem's historic plant compositional and structural diversity, reference surveys were undertaken of the natural coastal vegetation remnants of the neighbouring islands of Cousin, Aride and Praslin to determine which plant species, their distribution, stratification and in what quantities should be planted on Cousine. Information from Silhouette also provided some insight (Gerlach 2004). Coupled to this baseline study, were surveys of the seeds which were part of the high tide drift line on Cousine's beach, as well as those dropped (e.g. Ochrosia oppositifolia) on the Island by the Seychelles Fruit Bat (Pteropus seychellensis), which historically would have been part of the natural establishment process, as on Krakatau (Thornton 1996). There were some additional philosophical questions that needed to be incorporated into the restoration prject. The Coconut palm is an alien species. Against this background, it had been the intention to remove these aliens from the North Hill, South Ridge as well as most of the plain. Nevertheless, it was decided that some of these palms be planted along parts of the dune crest to provide nesting sites for the Brown noddy and, to a lesser extent, supply the Island with coconuts, as well as creating a tropical island atmosphere.
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While certain crop plants remain to this day in a demarcated area as produce for consumption on the Island, there is always concern that some may still spread. Among these is Papaya, which readily spreads and invades natural areas if not strictly managed. The spread comes about by seeds being dispersed in the digestive tracts of Seychelles skink, Wright's skink, Seychelles fody, Moorhen and giant tortoises, all of which feed on ripe, fallen fruit and on kitchen scraps. Certain crop plants, although a valuable food source, were considered to be too invasive to retain on the Island. Among these were Grenadilla and Guava which formerly occurred on the island, which were scheduled to be eradicated. It is important to emphasize that no chemical herbicides were used at any time in this alien plant removal programme. All alien plants were removed by hand and transported to a refuse pit where they were burned to destroy any seeds present.
The volunteer programme and monitoring activities An integral part of the restoration project was the initiation of an ad hoc volunteer programme in 1995 to assist the small number of staff on the Island with the manual removal of alien vegetation, and to help with the biological research and monitoring programmes. This exposed the restoration project to visitors as part of the rescuing the extinction of experience (Samways 2007). This first phase continued until the end of 1998, with eight volunteers participating. Currently, at least 14-20 human hours per week are required to continue to manually remove alien vegetation. Coupled to the actual doing of the restoration, was an important additional component involving biological research and monitoring (1995 to the present), so as to have a sound scientific data base followed by in-depth studies of the important and threatened species, and also to give advice on specific species. These projects also included coral reef surveys around the island. These activities of the first phase, for example, were undertaken by fifty-four visiting scientists from thirteen countries, whose time on the island varied from 1 to 126 days, with an overall total of 1131 working days.
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Propagation and planting of indigenous plants The clearing of alien plants was intimately coupled to propagation of seedlings and the establishment of new shrubs and trees in the weed-cleared, as well as formerly deforested areas. From 1995 onwards, all plants were propagated in a plastic tunnel from seeds or cuttings collected from both Cousine and its neighbouring islands. All the cuttings were treated with a rooting hormone (Seradix), and together with the seedlings, were supplied with micro-jet irrigation. There was no introduction of any rooted seedlings, so as to avoid any further introduction of alien organisms. Two exceptions were White hernandia (Hernandia nymphaeifolia) and Guettardia (Guettardia speciosa), which were collected as seedlings from Amitie on Praslin. Nevertheless, the seedlings were thoroughly washed on site to remove all traces of soil to avoid introduction of any unwanted micro-organisms and other invertebrates to Cousine. In the case of Tree heliotrope (Argusia argenta) and Suriana (Suriana maritima), and to simulate natural establishment, seeds that were collected from Aride Island and Bird Island respectively, were planted directly in situ on the dune crest slope of the southern beach. None survived, probably due to the sea erosion processes. Suriana did however, arrive naturally in 2000 by beaching seed, but by 2007, it had disappeared owing again to erosion of the dune crest base.
Aerial view of Cousine Island in 2007, with restoration well underway. Planting was done mainly in the North-west Monsoon rainy season (November to March). In several areas, mostly the sandy dune crest, temporary irrigation was used to ensure seedling and cutting establishment. This was particularly necessary along the East-facing dune crest, as this area is exposed to the drying effects of the strong South-east Trade winds. In addition, along this section of the dune crest, temporary shade-cloth barriers were erected to protect the plants from the effects of salt spray. These barriers were removed once the plants had established. In May 1996, a tractor-driven Hammer-mill was brought onto the island to control germinating coconuts and to shred fallen coconut fronds. This provided mulch that was distributed over most of the plain. This process continued for the next two years. A total of 2 543 trees and shrubs were planted on mainly the plain from 1993 to December 2001. Not all of these survived, and replanting was necessary at times over this period. After that date, at least another 755 trees were planted on the plain, with the aim of increasing the diversity of the vegetation cover. This planting programme continues to this day, especially along parts of the dune crest, where Casuarina trees have been removed. At any one time, about 200 saplings are available in the nursery for planting out.
Due to the nature of a relatively poor substrate, with the exception of the workshop/drainage line area, all plants required continual maintenance with regular watering, which, in most cases, was by hand. But where there was a water supply nearby, a temporary micro-jet irrigation system was installed.
Shade cloth barriers erected along the exposed dune crest to reduce the effects of salt-spray on newly planted trees and shrubs during the South-east Trades. In 1996, to conserve moisture around the young plants, 30 or more coconuts were placed around the base of each of the plants. These played an important role in reducing evaporation and providing suitable habitat for many invertebrate species. A total of 1 932 seedlings were protected in this way, using about 58 000 fallen coconuts.
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In addition, all plants had to be protected from introduced free-ranging giant tortoises which were able to destroy the seedlings and undo the restoration efforts in a matter of minutes. For this, the logs from the felled Casuarinas and occasional coconut palms were cut into 1-metre lengths and a minimum of two logs, depending on diameter, were placed around the base of each plant.
Bamboo removal While some plants, such as cotton, were relatively easy to remove, others proved to be much more difficult. The most intransigent of all has been bamboo (Bambusa vulgaris). While most has now been removed, some patches still remain. It was brought onto the Island prior to 1972, and began to dominate over 1 ha of the island, in dense clumps with a canopy from 5 to 10 m in height, and forming a thick litter layer of leaves and twigs. Except on the edges, no indigenous plants occur as undergrowth. About half the bamboo area was cleared by 1998, and the cleared area became naturally well vegetated with alien herbaceous plants such as Wild Grenadilla and Coromandel, while a number of indigenous trees were also planted, including Takamaka (Calophylum inophyllum), Figs (Ficus spp.), Pacific almond (Terminalia catappa) and Looking-glass tree (Heritiera littoralis).
Protective logs and coconuts around the bases of planted trees and shrubs.
A dense stand of bamboo in 1995 before removal. Destruction by burning, to destroy seeds, of the removed invasive alien plants.
Hammer-mill in operation, with the mulch being distributed from the left side of the mill.
Bamboo in the process of being removed.
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Clearing of the bamboo in 1996.
The same area as above in 2007; well wooded with a dense canopy and leaf litter layer.
Restoration of the coastal plain
The same area, as above, and on the previous page, in 1998, with a portion of the bamboo stand removed. In the foreground is a Coromandel herbland which had established after the clearing of bamboo and has since been planted with trees. The bamboo stand in the background was later also cleared.
Bamboo is particularly resilient and often re-grows after cutting and burning, and thus requiring a second round of removal.
Clearing of the coastal plain of cotton and other cultivated plants was followed by replanting with indigenous coastal tree species, including Takamaka, Pacific almond, Rosewood (Thespesia populnea), Fish-kill tree (Barringtonia asiatica), Indian mulberry (Morinda citrifolia), Ochrosia (Ochrosia oppositifolia), Coast cordia (Cordia subcordata), Pisonia (Pisonia grandis), Guettarda (Guettarda speciosa) and White hernandia (Hernandia nymphaefolia). Of these, the Fish-kill tree, Ochrosia, Guettarda and White hernandia have not been on the Island for many years. Wright's gardenia (Rothmannia annae) (Bowler et al. 2000) has also been planted in an attempt to establish a population of this rare endemic, known only from Aride Island, as a precautionary conservation measure.
The last remaining cotton plants on the North plain before their final removal.
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The North plain in 2001 after an extensive vegetation replanting programme.
The plantation on the northern edge of the coastal plain was an important nesting site for the Lesser Noddy. Its removal was delayed until such time as the planted indigenous trees were at a height suitable for these nesting seabirds. The manual removal of Spikeweed under the Casuarina canopy was initiated in 1995 and required repeated removal until it was totally removed by 1998. The ground cover then changed to the Little sticky-seed (Boerhavia repens) with some Coast grass. Interestingly, with removal of this northern plantation and control of Spikeweed, along with large numbers of nesting Lesser Noddies, a small number of Pisonia seedlings appeared amongst the Little stickyseed. These seedlings never did very well under the Casuarina canopy and remained at a height of less than 0.3 metres, until such time as the Casuarinas were removed in 2005, when they immediately flourished. The large Casuarina plantation (0.48 ha) was cleared in 1995 as the density of nesting Lesser Noddies was low and the birds could be accommodated elsewhere on the island. Some Pisonia seedlings were present but at a density far lower than those in the northern plantation, possibly related to the relatively poor substrate and the density of nesting seabirds. By 2008, all Casuarina trees had been removed from the Island.
The same view of the North plain in 2007.
Casuarina removal Another major alien plant community was that dominated by Casuarina (Casuarina equisetifolia) trees. These were introduced by humans in probably the late 1940s and possibly earlier. The population in 1995 was 227 mature trees in two plantations and along the dune crest, and their heights ranged from 20-30 m tall. They were fairly equally spaced and planted in rows, and making up a 100% canopy cover, and representing a density of 220 plants per ha. Casuarinas fringed the dune crest almost continuously from the south to the north beach. In 1995, there were two small plantations, one an aggregation on the northern edge of the coast plain (0.12 ha) and the other, the larger plantation (0.48 ha), on the plain, and extending from the dune crest to almost the base of the granite. Below the trees was a dense litter layer of Casuarina leaves and twigs. The ground cover in both areas was a dense stand of Spikeweed (Achyranthus aspera).
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Removal of the Casuarina plantation (0.48 ha) in 1995.
The restored site, in 2007, which was formerly a Casuarina plantation.
The area is dominated by alien trees, particularly Casuarina.
Restoration to the south of the pavilion The first step in the restoration of the area just south of the pavilion was the removal of the casuarinas. This was followed by demarcation of the new 'roads' linking some of the various infrastructures on the Island. These roads were later given to narrow (1.5m wide) concrete roadways to demarcate the travel routes, to a distance of just over 1 km. This construction was done for easy maintenance and to avoid flooded pools after heavy rains, which occurred on the former sand tracks and would have required precious soil fill at times. As soon as all the alien plants had been removed from the area, indigenous trees were established. Within ten years, a full canopy cover had developed, along with a substantial, moist leaf litter layer. This soon encouraged a variety of invertebrates also to establish, which, in turn, provided extra foraging area for the Seychelles magpie robin in particular.
The Casuarina plantation has been removed with some replanting of indigenous trees. The old sand tracks still remain.
The following series of six illustrations shows the vegetation changes with the passing of the years in the area south of the pavilion, photographed from the beach house area:
The vegetation is being restored with the establishment of indigenous trees.
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Restoration of the northern plain The northern plain was formerly dominated by Casuarina trees and a carpet of Spikeweed. Once the Spikeweed had been removed, a ground cover of indigenous Little sticky seed soon developed. Pisonia seeds, which had been dropped by Lesser Noddies, had established but were retarded by the Casuarinas. Once the conditions were improved by removal of the Casuarinas, the young Pisonia plants soon developed into a dense stand, interspersed with grass and Little sticky seed. The restoration process has progressed to a stage where the planted trees are beginning to resemble natural forest.
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The following three illustrations show a view from the north-east dune crest looking south:
The planted seedlings have now grown into young trees with full canopies.
The northern plantation of Casuarina trees with a dense ground cover of Spikeweed
Note the change in the developing forest floor from an exposed substrate with alien plants to a developing nutritious layer providing new habitats for invertebrates.
Spikeweed has been removed, with a ground cover of Little stickyseed taking its place. In this sunlit situation, seeds of Pisonia dropped by Lesser noddies have developed into seedling trees.
The following two illustrations give an aerial view of the eastern section of the plain and show how the planted trees have rapidly developed their canopies over the intervening eleven years:
After the Casuarina trees had been removed, the Pisonia trees soon formed a dense but low canopy on this windswept part of the Island.
Overall view of the restoration of the plain
Hill photopoint (1996) The plain has not yet developed its forest canopy.
In 1995, the central plain was very open and sunlit, and dominated by pioneer and alien plants. By 2007, the plain was already an exuberant cloak of forest, returning the Island to what is believed to have been its 'original' state. The following two illustrations show the rapid growth of plain forest on the central region of the plain:
Hill photopoint (2007): The forest canopy has now become well developed.
This plain is largely covered by pioneers and alien plants.
The plain now has a vigorous mixed forest canopy developing.
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Proportional changes in vegetation type from 1960 to 2007.
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Interestingly, with development of the coastal forest, and a substrate of felled alien logs, many fungi appeared, some of which had never been seen before on the island.
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A collection of fungi which appeared in the restored forest and forest gaps since the restoration programme has commenced.
Cousine's reprieve is nearly complete, with a green carpet across the Island, as seen by satellite in 2007.
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SPONGES, CORALS AND THE GREAT BLEACHING EVENT Invertebrates probably make up over 99% of all species, most of which are still not scientifically described. Even less well-known is their response to changing landscape and seascape conditions. From an invertebrate's point of view, there have been two major events on and around Cousine which have a great impact, one negative and one mostly positive, on their numbers. With the increasing sea temperatures by 2-3ºC in 1998 there was a great bleaching event, when many corals turned white and died (see p for more details) (Sheppard et al. 2005; Graham et al. 2006). We now consider this event in this chapter. The second major event was on land. The removal of alien plants and the establishment of indigenous trees have led to radically changed ecosystems, particularly on the coastal plain. We will consider this land event in a later chapter.
Sponges Sponges, as in the case of other intertidal and subtidal colonial organisms (such as corals), are homes for many smaller animals. In turn, sponges are a food item for various predators, including the Hawksbill turtle and various fish. A white cushion sponge grows in plates on intertidal granite boulders, while small sponges, such as an olive encrusting sponge, a bright blue cone-like sponge, and a flat veined-sponge (cf Echinochalina sp.) live in sheltered rock pools. A very attractive encrusting purple sponge occurs on some of the rocks and among the corals. However, the great coral bleaching event of 1998 severely reduced the sponge cover of the rocks. While there has been some recovery, by 2007, there was still not the extent of colourful sponges seen prior to that time.
Corals Hard corals, so called because they form colonies by building up a hard limestone skeleton, can form massive structures. A baseline study was undertaken on Cousine immediately prior to the great bleaching event and against which future studies can be compared (Samways and Hatton 2001). Fifty-one genera of hard corals have been recorded from the granitic Seychelles, 17 so far from Cousine. These include large rounded 'massive' colonies (e.g. Diploastrea heliopora), branched corals (e.g. Acropora austera, Pocillopora eydouxi) and flat corals encrusting rock, and other coral surfaces (Coscinaraea sp.), thin fan-like corals (Echinopora lamellosa) and mushroom-like corals (Fungia spp.). Of interest is the occurrence on Cousine of an internationally threatened species, the Organ-pipe coral (Tubipora musica), the skeleton of which is characteristically wine red in colour.
The dry skeleton of the Organ-pipe coral, Tubipora musica.
The colouful sponge gardens seen on the rocks prior to the great coral bleaching event of 1998.
Many of these species were severely affected by the great bleaching event of 1998, although slow recovery is now taking place. Of particular concern was whether the globally threatened Organ-pipe coral had survived. In surveys around Cousine in 2007, the species was rediscovered, an encouraging sign of seabed recovery. By September 2008 several colonies had established, with first one also having reached a diameter of over 90 cm. Regrettably, these colonies were poached for the tourist market in early 2009.
Tropical Island Recovery: Cousine Island, Seychelles.1st edition. By Michael Samways, Peter Hitchins, Orty Bourquin, and Jock Henwood. Published 2010 by Blackwell Publishing Ltd.
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Organ pipe coral alive and well nine years after the great bleaching event of 1998.
Echinopora gemmacea at the foot of the slope in 1998. This large colony died in the great bleaching event, and has not been seen since.
A colony of Diploastrea heliopora in deeper water at the foot of the slope. This colony, believed to be well over a thousand years old, died in the great bleaching event of 1998.
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A colony of Pavona clavus in 1997 growing in a more stable part of the reef system. It survived the great bleaching event very well.
Mushroom coral, Fungia scutaria is a common inhabitant of the sea bed nine years after the great bleaching event. Coral form varies enormously depending on the amount of wave action it experiences. This is particularly so in staghorn corals like Acropora robusta and A. formosa which can be branching and spike-like in still water, but dwarfed and rounded in the surf zone.
A group of corals: Acoropora formosa in the background; Pavona clavus in the centre; Acropora robusta on the left, and Pocillopora eydouxi on the right.
Different growth forms of Staghorn corals: Acropora formosa in the foreground with A. robusta behind are branched and spiky in still water (top) but dwarflike and rounded in the surf zone where it adapts to moderate (middle) or strong (bottom) wave action where the water is also very cloudy.
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Some familiar corals of Cousine: Montipora digitata (top left); Acropora austera in foreground and A. formosa in background (top right); A. gemmifera in top centre and Pocillopora damicornis in bottom centre (middle left); Stylophora pistillata in bottom left and A. formosa in top right (middle right); Pavona clavus (bottom left); Lobophyllia hemprichii (bottom right).
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More corals of Cousine: Symphyllia recta (top left); Porites ? lutea (top right); Echinopora gemmacea (bottom left); Diploastrea heliopora (bottom right).
Anemones and zoanthids Anemones are fairly common inhabitants of the coral reefs and submerged granitic boulders, around Cousine. The Skunk anemone fish (Amphiprion akallopisos) is associated with large sea anemones, usually with the Magnificent sea anemone (Heteractis magnifica), an anemone up to 50 cm wide, while the Seychelles anemone fish (Amphiprion fuscocaudatus) is associated exclusively with Mertens' sea anemone (Stichodactyla mertensii), perhaps the worlds largest anemone, often exceeding 1 m in width. While these species were present prior to the great bleaching event, they disappeared thereafter and had not returned by September 2008, 10½ years later.
Magnificent sea anemone with attendant Skunk anemone fish. Other common, plant-like growths are mats of spongy green, blue or brown zoanthids (Zoanthus sp.). These animals are related to corals, jelly-fish and seaanemones. Zoanthids filter feed on tiny prey using tentacles around the mouth, but, like corals, most depend on miscroscopic algae in their tissues for much of their nutrition. Zoanthids are colonial, the individuals (polyps) being joined together at the base. The mats offer shelter to a wide variety of small invertebrates, including bristleworms, shrimps and amphipods.
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LIFE IN THE SHALLOW SEA: FROM SHELLS TO URCHINS Chitons The intertidal granite boulder area is the home of chitons, primitive molluscs with a flattened body and eight plate-like shell valves, surrounded by a skirt, known as the girdle. They have a broad foot which can adhere tightly to rocks allowing them to withstand considerable wave shock. The head is completely hidden beneath the girdle surrounding the valves, and lacks eyes and sensory tentacles. They feed on encrusting plants and animals, rasping them off the rocks with a file-like tongue or radula. Both the Blackscaled chiton (Chiton sp.) and the Hairy chiton (Acanthopleura cf gemmata) occur around Cousine, adhering to rocks. The Black-scaled chiton is black above, with a cream girdle covered with fine scales, and is 40 mm long. The valves are up to 19 mm wide, and each peaked in the centre. The animal is triangular in cross-section. The Hairy chiton is much larger, up to 70 mm long, and has somewhat roughened plates. It has a black girdle with numerous short, simple outgrowths dorsally, giving it a hairy appearance. The valves are slightly rounded and are up to 40 mm wide. They are brown, patterned with darker brown, with a lighter centre flanked by pale
bars.
cowrie (C. moneta), Tiger cowrie (C. tigris), Honey cowrie (C. helvola), Serpent's head cowrie (C. caputserpensis), Dawn cowrie (C. diluculum) and Mole cowrie (C. talpa) occur on shallow reefs. Cowries are herbivorous, or feed on sponges. Thin extensions of their body, which may be dramatically coloured or textured, can be extruded completely over the shell of the living animals.
Various cowries, Honey cowrie (top left), Money cowrie (top right), Serpent's head cowrie (bottom left) and Dawn cowrie (bottom right).
The Actor cowrie.
Hairy chiton.
Sea snails Cowries are favourites with shell collectors and souvenir seekers. Many are large and colourful. Some species are found in the in intertidal zone, while others, like the Carnelian cowrie (Cypraea carneola), Arabian cowrie (C. arabica), Money
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Among the whelks, which are all scavengers or predators capturing their prey with a tubular proboscis, are some strikingly shaped shells with spines or branched outgrowths, such as the Branched murex (Chicoreus lambis). Such outgrowths are also present in some conches, such as the Orange spider conch (Lambis crocata), and the Arthritic spider conch (L. chiragra arthritica), which feed on microscopic algae.
Tropical Island Recovery: Cousine Island, Seychelles.1st edition. By Michael Samways, Peter Hitchins, Orty Bourquin, and Jock Henwood. Published 2010 by Blackwell Publishing Ltd.
The cones are predators and use hollow, harpoonlike teeth to inject a neurotoxin into their prey. The Tent cone (Conus aulicus) and Geographer cone (C. geographus) can be poisonous to humans, as their rasping tongues are modified into a barbed harpoon. The Geographer cone is even potentially lethal. The toxin of this cone is so stable that it is dangerous to humans even after the animal is dead. Indeed, all cones should be handled with extreme care. Many of them live in sand in shallow waters, particularly in rocky or coral areas. Favourite food items of many species are bristleworms. Others feed on molluscs. The Arthritic spider conch.
The Tent cone.
The Arthritic spider conch seen from below.
A representative of the auger shells is the Spotted auger (Terebra maculata), found to a depth of 10 m. These snails have a harpoon-like radula and a long poison gland as found in the cones. Their prey is said to be acornworms and bristleworms, which are subdued by an injection of venom before being eaten.
Natural mortalities of the Branched murex have been observed on Cousine. This has been the result of Hawksbill turtles coming up the beach to nest, and while doing so, have transported the molluscs which fell off the carapace and succumbed on the beach.
The Spotted auger.
A specimen of the Branched murex, with barnacles attached to it, on the carapace of a turtle.
Many marine molluscs occur in the intertidal zone, including the Banded limpet (Cellana livescens), False limpet (Siphonaria sp.) and Rayed limpet (Patella pica). The Banded limpet is common on the granite, grazing over the surface during the wet periods, and sealing itself down during the low tides. The Rayed limpet returns to a chosen spot on the rocks and is often partially embedded in the rock surface. Its shell is generally covered with living seaweeds and other growth, making it well camouflaged.
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The Striped periwinkle (Littoraria glabrata) is a common, desiccation-resistant species, often found well above the high spring tide level. Other molluscs live in cracks in the rocks, and include the Blotched nerite (Nerita albicilla), with its white interior and variable patterning, the Textile nerite (Nerita textilis), Smooth nerite (Nerita polita), and Toothed nerite (Nerita plicata). The Grey nerite (Nerita undata) can be found in sea caves or deep overhangs, often well above the high tide level. All these animals are herbivorous.
Few have been named from Cousine, but those that have include the True bubble (Bulla ampulla) and a wide-spread, beautiful tropical nudibranch Hexabranchus sanguineus, called the Spanish Dancer, which, uncharacteristically for the group, swims with undulating movements and so displays its bright red and whitish body markings.
The Spanish dancer. Common Nerites of the intertidal zone Smooth nerite Textile nerite Blotched nerite Opportunistic feeders on the intertidal rocks at low tide include carnivores feeding on molluscs such as the Granulated morula (Morula granulata), and the Window cronia (Cronia fenestrata). Numerous other molluscs live in the intertidal zone, but shelter in moist areas under rocks or in crevices to avoid desiccation. Some juveniles of deeper water species develop in the intertidal zone. Species in the rubble-strewn, intertidal flats include various cowries and nerites, the names of which are given in the Checklist.
Nudibranchs and sea hares Among the most colourful marine animals are the nudibranchs and sea hares. They have a general reduction or complete loss of the shell. Their bright colours are a defensive mechanism, indicating to potential predators that they are toxic by having powerful defensive chemical poisons or by reutilising stinging cells derived from their coelenterate prey. The feeding habits of nudibranchs and sea hares vary enormously, some being herbivores, some scavengers, and others specialist predators on various prey, including sponges, flatworms, marine worms, shrimps, and even other types of nudibranchs.
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Bivalves The two-shelled, bivalve molluscs are not numerous around Cousine, although the Imbricate pearl oyster (Pinctada imbricata) and the Black pearl oyster (Pinctada nigra) occur in the subtidal areas. A very attractive small bivalve, the Thorn oyster (Spondylus sp.), has been found on floating objects. It has thin spines angling off from the shells. Two species of giant clams live around Cousine. Both are important species from a conservation viewpoint, and are protected internationally. This protection is necessary because their shells are a favourite memento for purchase by tourists, while the meat is a food item for many people in the Indo-pacific. The Elongate giant clam (Tridacna maxima) has well developed concentric growth folds with green to dark blue mantle folds, and grows to 300 mm in length. The Fluted giant clam (T. squamosa) has rows of large, leaflike flutes, and can grow to 400 mm in length. Both can occur in shallow water to 20 m in depth. Giant clams filter-feed as well as farming microscopic algae under their mantles, and from which they derive nutrition. Interestingly, known individuals of giant clams survived the great bleaching event and were alive in 2007, nine years later, and testament also to their longevity.
A giant clam in January 1998, filter feeding while embedded in coral rubble.
Shipworm damage to wood washed up on the shores of Cousine
Octopuses, squids and cuttlefishes The same clam individual in April 2007, although the hard coral around it has since died in the great bleaching event. The Shipworm (Bankia sp.) is an unusual bivalve which bores into wood of ships and submerged or floating logs. The animal is elongated, occupying burrows lined with a chalky shell material in wood, which can become so riddled with holes that it eventually disintegrates. Although the shipworm can filter-feed, it is also able to digest wood with the help of bacteria in its gut.
The octopuses (such as Octopus sp.) are bottom dwellers, while squids and cuttlefishes forage near the bottom or in open water. Squids are more slender and delicate than cuttlefishes and have a reduced shell looking like a transparent pen under the skin at the top of the animal. The cuttlefish bone is large, broad and chalky on the undersurface. Both octopuses and cuttlefishes are common in the subtidal zone, although there is concern that they are being overharvested, not just around Cousine, but throughout the central Seychelles. Squid (Loligo sp.), known as calamari in culinary circles, are occasionally brought onto the island by White-tailed tropicbirds to feed their chicks. Squids have eight arms and two non-retractile tentacles. Squid are predators on small fish and are themselves an important food source for fish as well as for seabirds.
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On Cousine, this barnacle has been found on floating objects as diverse as Takamaka seeds, compressed rubber and plastic shoes, and blocks of
Octopus is harvested by the local fishermen around Cousine and sold on Praslin. The favoured species and specimens are generally larger than this one, with a body length of about 12 cm.
Goose barnacles attached to a piece of floating rubber
Marine worms Bristleworms Under the debris on the sandstone flats are numerous bristleworms. They are diverse in structure, and all have a head with a snout-like projection, and a cylindrical front segment that surrounds the mouth. In some species, the heads are elaborately modified into a beautiful fan or tufts of tentacles used for feeding. The body is divided into segments, each with a pair of lateral leg-like protuberances with bristles. Fertilization is external and the larvae are tiny and planktonic. Bristleworms occur under rubble in sand on the sandstone pavement and under mats of zoanthids. The colonies of interwoven hard white calcareous tubes seen on coral or rock belong to bristleworms. These tube and coral worms are particularly abundant on intertidal rock and old coral surfaces. Some, such as the Palolo-worm (Eunice sp.) are carnivorous, and with large jaws, can inflict a nasty bite. Thin, white spider-like tentacles which spread out from sandy tubes in rocky crevices indicate presence of a Medusa tangleworm (Loimia medusa), living in
Barnacles The Goose barnacle (Lepas sp.) has a flattened body, five white shell plates, and a stalk which is fixed to the substrate. It lives in dense colonies on the hulls of ships, or on any other hard-surfaced small to large floating object. The common name derives from the myth that it grows into Barnacle geese!
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The Pink-striped barnacle (Balanus sp.) is turretshaped with a pink- and white-striped shell, which has alternate upside-down and right-way-up triangle patterns. It has been found on mooring buoys off Cousine and one individual was even found on the tag of a nesting Hawksbill turtle. It is also common on coral heads. Other barnacles commonly occur on hard corals such as Acropora austera and Coscinaraea sp., on mollusc shells, and on boulders, to a depth of 10 m. Some of these are probably the same pink-striped barnacles found on floating objects. Others burrow into calcareous rock, corals and even shells of other animals. These burrowing barnacles differ from other barnacles by a reduction or absence of the calcareous plates. Location of their burrows is visible from the outside by a slightly raised area and a small slit. A number of permanent inhabitants occur on the granite boulders. The most abundant is the tiny Toothed barnacle (Chthalamus sp.), under 5 mm long and covering large areas of rock. Scattered among them is the Volcano barnacle (Tetraclita sp.), while in sheltered areas under intertidal overhangs small colonies of the Giant plated barnacle (cf Austromegabalanus sp.) are occasionally found. This 600 mm-long barnacle cements itself strongly to the granite substratum, and its six dorsal plates are hinged and toothed.
Lobsters
The Toothed barnacle is very well able to withstand strong wave action and moving sand.
Isopods and amphipods Isopods are small crustaceans, some of which are parasites and cling to fish. Others live in water under rocks, in sand and on seaweeds, while others occur out of water on intertidal rocks. They feed on a variety of food items including seaweed, carrion and live prey. Amphipods are common in the intertidal zone. These small animals are flattened from side to side, unlike isopods which are flattened top and bottom. The first two pairs of legs are generally formed into tiny nippers, and most amphipods live in seaweed or in sediments, feeding on detritus or carrion.
Spiny lobsters are large crustaceans with a long tail ending in a well-developed tail fan. None of the walking legs have nippers. They are sometimes called crayfish, but are correctly called spiny lobsters. Spiny lobsters have an elaborate life cycle involving thirteen larval stages and many months floating in the sea before metamorphosis into the adult stage. Four species of rock lobster occur in the Seychelles and are fished by the local people. The dominant one is the Pronghorn spiny lobster (Palinurus penicillatus), which occurs throughout the Indo-Pacific. Others around Cousine include Long-legged spiny lobster (P. longipes) and the Painted spiny lobster (P. versicolor). None of these species is common, and it is believed that harvesting pressure has drastically reduced their numbers. The Pronghorn spiny lobster can occur in groups among coral in shallow water. This species has dark antennae usually has longitudinal striping on its legs, and has a white-spotted abdomen with a row of characteristic large white spots along the sides of the abdomen.
Shrimps, prawns and lobsters Mantis shrimps Mantis shrimps are highly specialized. They are swift predators with massively developed spined second front legs, resembling a praying mantis. Some species spear soft-bodied prey such as small fish using the spines. Other species seldom have spines, but use the modified legs to smash down on hard-bodied prey, stunning or killing them. Mantis shrimps live in burrows or in rock or coral crevices. The abdomen is flattened and large. The bright Green mantis shrimp (Gonodactylus sp.) lives under rubble on intertidal flats.
Long-legged spiny lobster. The beautifully marked Painted rock lobster is patterned in green or blue, and black and white, with long white antennae. The Long-legged spiny lobster has grooves running across its white spotted abdominal
Painted spiny lobster.
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Snapping shrimps Some Snapping shrimps are associated with some hermit crabs (Dardanus spp.), in the same sea shells. They are small (to 28 mm full stretch, nippers extended) maroon and white shrimps with a large left nipper which is held with the curve pointing upwards. This is the Dardanus shrimp (cf Aretopsis amabilis). Usually only one, but occasionally two occur with each hermit. Members of this family often display commensal relationships with other organisms, particularly gobies.
The mouth is situated at one end and is surrounded by retractable, branched feeding tentacles, which are withdrawn inside the mouth when feeding is not in progress or when the animal is disturbed. Bands of small sticky tube feet run the length of the body, and are used for locomotion and to cling to the substrate, or to hold debris such as sand grains onto the body surface as camouflage. Most commonly seen is the large (up to 30 cm long) Variable sea cucumber (Actinopyga mauritiana) which is plain yellowy brown, dark brown, or brown on top and yellow brown on the sides. It has a white ventral surface, except for the head, which is dark.
Other prawns and shrimps Other Snapping shrimps are free-living, with the Cracker shrimp (Alpheus sp.) common in the rubblebeds. It has a shiny brown body, and burrows among and under stones. Its left nipper is well-developed and makes an audible click when snapped shut, and causing a spout of water. The Striped prawn (Penaeus caniculatus) occurs in the lake which forms on the south beach during part of most years. It is active at night in the shallow edges, sometimes burying itself in the sand when disturbed, or leaping out of the water to avoid being caught. The young prawns are semitranslucent and white, while the adults have orangebrown bands. Shrimps are not good swimmers, and generally live on the sea bed. A pretty Banded zebra shrimp (Gnathophyllum sp.) lives among the rocks, as do several species of cleaner shrimps, which are delicate, brightly coloured animals, and are also common in the reef area.
A green form of the Variable sea cucumber.
Sea cucumbers, starfish, brittle stars and sea urchins Sea cucumbers Except for a few conspicuous species, the Sea cucumbers are often overlooked, as many species cover Ventral surface of the Variable sea cucumber showing themselves with sand particles, held by mucous, the whitish area rich in tube feet and black head making them difficult to detect. They have an elongate, region. sausage like body covered with a soft leathery skin.
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Variable sea cucumber, bicolour form, in a rock pool. Other common species include the Black sea cucumber (Holothuria atra) which covers its shiny black body with sand grains, camouflaging itself adeptly. The Dark green warted sea cucumber (Stichopus chloronotus) has numerous elongate "warts" (papilla) projecting from its body and is angular rather than rounded in shape.
The Dark green warted sea cucumber is commonly seen on the coral rubble.
Populations of sea cucumbers on the fringing reef have been reduced by local divers in recent years for export to Asia. This is of concern, especially as the offshore areas around Cousine are not a proclaimed protected area.
Black sea cucumber.
Starfish Starfish are not common around Cousine, although the most frequently seen is a large (up to 400 mm wide) yellow or blue starfish, the Common star (Linckia laevigata), usually on offshore rubble. It is widespread in the Indopacific, scavenging and also feeding on algae.
The Common starfish is a common inhabitant of the fused coral rubble, and appears to have been little affected by the great bleaching event. A pretty, small starfish, the Eyed star (Neoferdina offreti), with a pinky yellow colour and maroon spots on some of the dorsal plates, occurs on the coral reef at about 10 m depth. It grows to a width of 110 mm. Interestingly, there is no evidence that either the starfish or the sea cucumbers declined as a result of the great bleaching event of 1998.
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Brittle stars One of the common inter-tidal organisms, especially on the calcareous flats, are Brittle stars. These have five sinuous slender arms, arranged around a central disc. The arms break off easily, hence their general common name. The mouth is on the underside of the body and is surrounded by five-toothed jaws. Most feed on detrital particles. Several brittle stars have so far been found around Cousine, the most common of which is the Granular brittle star (Ophiocoma scolopendrina), which is usually variegated black and white, sometimes completely black.
Ventral surface Dorsal surface Granular brittle star
These spines are arranged in broad rows down the shell, separated by narrow rows of dark red, where the spines are absent.There was a change in the sea urchin assemblage after the great coral bleaching event of 1998, with a shift to the most dominant species on the coral rubble (where there had once been reef) to the Black needle urchin (Diadema savignyi). It appears to favour disturbance, as it can be common in harbours elsewhere in the Seychelles.
A Black needle urchin, almost invincible with its long spines and nestled among the coral rubble left behind after the great coral bleaching event of 1998.
Sea urchins The sea urchins mostly have globular bodies encased in a calcium carbonate shell, covered with spines. The mouth is on the underside, while the anus is usually on the upper surface. Most rocky-shore urchins are grazers on algae. A common species in the intertidal zone is the Banded urchin (Echinothrix calamaris) which has black and white banded, (or pure black when adult), long, thin, hollow, spines. These spines easily penetrate skin and contain an irritant toxin. Similarly, the Slate pencil urchin (Heterocentrotus sp.) has black and white bands on its spines (sometimes completely black). It has two kinds of spines: one is thick and blunt with open tips, while the other is very fine and needle like, with microscopic downward pointing barbs. As with the Banded urchin, the Slate pencil urchin should not be handled. A third, less obvious species is the Red-andwhite urchin (Tripneustes cf ventricosus), a small, rounded urchin with short, white blunt spines.
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Slate pencil urchin
Banded urchin
A group of sea-urchins called cidaroids have characteristically thick, solid, club shaped spines (up to 30 mm long). The only representative so far found on Cousine is the Banded-club urchin (Eucidaris metularia) which lives in crevices, usually in shallow water. The spines are pinkish, each with two to three pale, narrow bands. An urchin of the granite intertidal zone is the Oval black urchin (Echinometra mathaei), which has an oval shell and shortish, black, sharp spines (up to 40 mm long). It occupies hollows and holes, catching drifting algae or emerging at night to graze. The Protea urchin (Colobocentrorus atratus) is a most unusual looking urchin, with black spines in the form of plates covering most of the shell and a fringe of flat spines, black above and purple below, around the base. The urchin lives on the granite intertidal area and its shape, and its very strong, clinging behaviour enables it to withstand strong wave action.
The Protea urchin. dorsal surface
The Protea urchin: ventral surface
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BETWEEN SEA AND LAND: A VARIETY OF CRABS CONTENTS Hermit crabs The empty shells of molluscs are used by various species and ages of hermit crabs. The hermits use the shells as homes to protect their soft-skinned abdomens. To fit into the spirals of some of the shells they occupy, some hermits have developed a twisted abdomen and the appendages on the inside of the curve have been reduced or lost. In some hermits, the nippers are of equal size, while in others the left one is enlarged, as in the land hermits (Caenobita sp.). Most species are scavengers. A number of hermit crab species abound around Cousine, especially in the intertidal zone and in subtidal areas.
Tent cone shell, home to the White-spotted hermit crab and two Dardanus shrimps. Associated with the hermit crab, and found in the shells with these hermits are two small maroon and white shrimps with a large left nipper which is held with the curve pointing upwards. These are the Dardanus shrimps (Aretopsis amabilis) which generally display commensal relationships with other organisms, particularly gobies.
Hermit crab foraging at sunset, and making its typical tracks. A common hermit crab in deeper water is the Whitespotted hermit crab (Dardanus saguinolentus). This hermit occurs to 12 m in depth, occupying empty shells such as Conus. It is maroon in colour, with small white spots on the cephalothorax. The nippers are spiny and are covered with stiff, white-tipped maroon hairs, as are the legs. Eyestalks are greyish-yellow, with yellow around the base of the black eye. The antennae are blue. The legs are maroon, mottled with white, and there are two conspicuous black bands at the base of each walking leg.
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A Red hermit crab removed from its shell.
Tropical Island Recovery: Cousine Island, Seychelles.1st edition. By Michael Samways, Peter Hitchins, Orty Bourquin, and Jock Henwood. Published 2010 by Blackwell Publishing Ltd.
Hermit crabs from the intertidal areas include the Red hermit crab (Dardanus megistos). This hermit occurs on the rubble flats near the sub-tidal area. The nippers and walking legs are covered with red and brown bristles. It has an orange-red body covered with white spots, each encircled with black. The Yellowbanded hermit crab (Clibanarius virescens) has greygreen hairy nippers, spotted with white nodules. The legs are olive banded with yellow towards the tips. Eyestalks are olive with a narrow white band before the eye, and the antennae are blue. It is common on the rubble flats. A small species, the Blue-eyed hermit crab (Calcinus laevimanus) is common around Cousine, and has smooth chocolate brown and white nippers. The extremities of the legs are banded creamy and dark brown, the eye-stalk is orange and has a blue base. The antennae are dark yellow in adults, and pale yellow in juveniles, which also have the chocolate colour missing from the nippers, leaving them pure white. There are four other small hermit crabs, which are not yet identified. The White-eyed hermit crab lives on the rubble flats and has smooth white nippers and eye stalks, yellow antennae and the ends of the legs are yellow, dark brown and pinkish. The Purple-banded hermit crab is uncommon, being found in Turbo shells on the rubble flats. Its enlarged nipper is salmon coloured and has nodules, some almost spinous. The walking legs are purplish brown, with sparse yellow hairs, the eye stalk is white with a purple band, and the antennae are pale brown. The Gorgeous hermit crab lives in Thais and Vascum shells among granite boulders in the intertidal area on the southwest coast and on the north point. The left nipper is olive with white nodules covering the tips. The antennae are orange. The eye stalks are dark blue with a black base. The legs are sky blue with black dots, with a broad black band on the second to last digit and stiff brown bristle clusters on the undersides of the legs. The antennae are very short, being just over twice the eyestalk length. A relatively uncommon hermit crab which has been found in Achatina and Conus shells on the rubble flats is the Sharp-clawed hermit crab. The left nipper is square-shaped, creamy with some grey dorsally, and is finely serrated along the top.
The last two digits of the olive-grey walking legs are sharp edged, the edges being minutely serrated. The eyestalk is olive with a purplish-black band and the eye is shining dark olive. Three species of Land hermit crabs occur on the beach and dunes. Although living most of their adult lives on land, they go back to sea to spawn or, when necessary, to obtain moisture. The large left nippers are used to block the entrance to their borrowed homes after they have withdrawn into these to escape predation or to conserve moisture. The Pearly hermit crab (Coenobita perlatus) lives on or just behind the dune crest, foraging there, on the beach and in the intertidal area. It is cream and orange, and the enlarged left nipper has the dorsal surface covered with nodules. It has broad, flattened white and orange eye stalks.
The Pearly hermit crab foraging on the dune crest. The Rough hermit crab (Coenobita rugosus) has similar habits to the Pearly hermit crab. Its enlarged nipper is pale with varying degrees of grey or pale mauve. The dorsal surface of the nipper is covered with evenly spaced round nodules and the eyestalk is flattened and white.
An alert and mobile Rough hermit crab.
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The third Land hermit is the Short-hand hermit (Coenobita brevimanus), which is common behind the dune crest, often some distance from the sea. It forages mainly after dark, often occupying shells of Turbo and, during the day, shelters under logs or rocks. The large left nipper is purple in colour, and the dorsal surface is smooth in young animals, but gets nodules as the animal ages. One of its features is that the eyestalks are rounded and dark purplebrown, unlike the flattened, pale eyestalks of the Rough and Pearly hermit crabs.
Short-hand hermit crabs sheltering under a log.
Short-hand hermit crab accessing a new shell.
True crabs
A Short-hand hermit crab occupying a coconut shell.
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True crabs are the familiar free-living crabs, common in the intertidal rubble beds and on the granite boulders. During the day, a large multi-coloured crab may be seen scuffling around the granite boulders. It will also forage on shallow soiled, vegetated areas near the boulder edges. This is the Rock crab (Grapsus tenuicrustatus).
Rock crab.
Storm's rock crab.
During the night, a related species, the Tan rock crab (Geograpsus crinipes) emerges from its shelter from under rocks or damp crevices and forages along the water line in rocky areas. It has also occurs well away from the shoreline in sheltered conditions, and has been recorded attacking and feeding on a Seychelles giant millipede in Pisonia forest, and even a newly hatched Moorhen chick. This large crab has a carapace width of up to 70 mm and is pinkish, tan or red in colour.
A common inhabitant of the intertidal sandy beaches and sometimes inland beyond the dune crest is the Horn-eyed ghost crab (Ocypode ceratophthalmus). It can attain carapace widths of nearly 50 mm, and weigh up to 65g.
Horn-eyed ghost crab. The stalks on the eyes are not present in juveniles, but start developing when the carapace width is about 25 mm.
Tan rock crab. A smaller species of rock crab is Storm's crab (Geograpsus stormii), with a rich maroon carapace and reddish brown legs. It is a rock crevice dweller with a flattened body. Horn-eyed ghost crabs feeding on a dead white tern.
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The Horn-eyed ghost crab usually starts foraging in the evening, although the young may forage during the day. Adults may also forage during the day in overcast conditions. Although usually scavengers, the Horn-eyed ghost crab will catch, kill and eat sea-turtle hatchlings during their debut run from nest to sea. Some will also dig into turtle nests to feed on eggs, embryos or hatching turtles.
it forages and establishes burrows on the coastal plain and among the granite. It is a scavenger and a predator consuming a wide range of foods from kitchen leavings to giant millipedes. It also attacks turtle eggs, embryos and hatching turtles. Whole clutches of turtle eggs have been destroyed by this species, which will enter the nest from burrows started at the nest, or laterally through underground burrows. Two buckets sunk into the sand nightly next to a turtle nest and baited with raw fish, trapped no less than 472 Dark ghost crab individuals over 15 days. It is possible that this crab, on Cousine, and elsewhere in the Seychelles, is having a deleterious effect on successful turtle breeding, albeit a natural process.
Horn-eyed ghost crab eating a Hawksbill turtle egg. The Horn-eyed ghost crab burrows are usually made above high tide mark, but some individuals will make burrows in the inter-tidal zone. During low tide the burrows are cleared by the occupant, which uses its nippers and its first two pairs of walking legs to cradle a load of sand, which it then deposits in a neat pile a meter of so from its burrow entrance. When running at full speed, the crab lifts its last pair of legs off the ground and points them into the air.
Dark ghost crab at its burrow entrance under a granite boulder. In 2002, the Pink ghost crab (Ocypode ryderi) was discovered on Cousine Island. This is a first record for the Seychelles. It has a pale pink body with distinctive mauve joints to the legs. It presently occurs in low numbers mainly on the lower parts of the north beach.
A Horn-eyed ghost crab at its burrow on the intertidal beach. A more robust species, with a carapace width of up to 60 mm and approaching 100 g in weight, is the Dark ghost crab (Ocypode cordimana). It prefers the higher, elevated beaches, the dunes and the back beach, where
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Pink ghost crab.
The majority of true crabs are aquatic or at least virtually so. These include swimming crabs in which the last pair of walking legs end, not in claws, but in paddles. Many of these are aggressive, ever ready to snap with their long, sharp nippers. Large specimens can easily cut through human skin and tissue. Of this group, three species occur in the intertidal zone. These include the Red-spot swimming crab (Thalamita sp.) whose body colour is variable from plain cream to pinkish red, or with fine reddish spots and patterns, with or without conspicuous large red solid marks. It has five spines along the edge of the carapace and six blunt projections between the eyes, with the second projection from each end being flat and about twice the width of the others. Two spine ridges are on the nippers upper edge, and the nippers are banded greyish black and white. It is a common species which shelters under coral and rubble during low tides. It grows to 26 mm carapace width. The Snapper swimming crab (cf Charybdis sp.) is a larger swimming crab (over 50 mm carapace width), and is also found on the rubble flats. It is aggressive, ready and eager to snap at unwary fingers. The species has clouded olive carapace with soft brown and reddish markings. The nippers are large, have two spined ridges on their upper edge and are black with orange tips. The edge of carapace has four spines and there are six blunt, rounded, low projections between the eyes.
The eyes of the Wide-eyed swimming crab (cf Thalamita sp.) are almost level with the outer edges of the carapace which is cream to maroon with red to purple markings. The nippers are black with white tips and have two spined ridges. The carapace has four sharp spines, and the area between the eyes is flat with a small central notch. In 1995, thousands of Pink swimming crabs (scientific identity uncertain) were washed up on Cousine's beach. This may have been due to strong, onshore turbulent conditions at sea. These crabs are between 35 to 40 mm carapace width, overall pink in colour and have six teeth on each edge of the carapace, the last posterior one being twice as long as the others, and six teeth interorbitally. The nippers are ridged dorsally with one to two large spines and numerous blunt small ones. Common in rubble and rocky areas in the intertidal zone are the coral crabs among which are some large species. The most conspicuous is the Red-eyed coral crab (Eriphia laevimanus), with large chocolate coloured nippers bearing heavy, blunt, white teeth. The eye stalks are red. This species is often found above water level, foraging slowly on the damp rocks. It can reach carapace widths of 70 mm or more.
Red-eyed coral crab.
Snapper swimming crab.
The Pretty poison crab (Zosymus aeneus), which can attain 80 mm carapace width, occupies the intertidal zone or shallow water beyond this in rocky or usually coral areas. The species is variable in colouration, usually multicoloured with red to brown spots and other markings on a pale to dark background. The carapace is lumpy, with four broad blunt spines on the edges and a slightly curved edge, between the eyes, and which is notched centrally. The crab is poisonous if eaten.
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The pretty poison crab. The Short-eyed xanthid has been found in damp granite crevices, well above high tide mark in the splash zone. It is an attractive species, with reddish, grey and cream patterns on the carapace which is "lumpy" towards the front edge, where olive colours some of the grooves between the lumps. Its legs are banded red and white, and the nippers are heavy, reddish brown above and greyish white below. The abdomen is greyish white with red markings. The edge of the carapace has five wide, blunt teeth and there are four blunt projections interorbitally. Crabs of coral reefs include the Large spotted coral crab (Capilius maculatus), a distinctive, large (to 140 mm carapace width) greyish to yellowish-brown crab, with large red-brown spots. The Eyed coral crab (Atergatis subdentatus) is smaller (to about 90 mm carapace width) with an orange, finely pitted carapace, which usually has a darker orange spot in the centre, sometimes with two small white eyes in the spot.
Large spotted coral crab (left) and the Eyed coral crab (right) carapaces, washed up on the beach.
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Other small (under 25 mm) lumpy crabs include at least five species, of uncertain scientific identity. The White-spotted coral crab has small, flat, grey-white nodules on the carapace, and the Grey bump coral crab has greyish brown nodules on the carapace. The Whitebanded coral crab has a broad band of white nodules across the carapace, while the Strawleg coral crab has its legs covered with long straw-coloured hair-like projections, and has shiny red brown nippers and anterior carapace. Finally there is the Tomato crab, socalled because of its cherry red carapace and legs. There is an interesting group of crabs on the Island which decorate themselves with seaweeds, coral, anemones, tunicates, hydroids and marine detritus. These are the Decorator crabs which have triangularshaped carapaces and slender legs. The Yellow decorator crab, White-flecked decorator crab and Long-horned decorator crab all occur in the inter-tidal rubble flats, while members of the same family are also present in the granite inter-tidal zone. The Yellow decorator crab grows to about 20 mm long, is yellowbrown all over and has three equally long horns on top of the elongated carapace. These horns are usually decorated with bits of brown algae held there by comblike hairs. This decoration probably confers camouflage and protection from large predators such as certain fish. The White-flecked spider crab is of similar size, but its crown of horns is shorter and broader, and has a brown body, with white flecks on the carapace and legs. The smallest species (about 8 mm long) is the Longhorned spider crab, with a central horn much longer than the two flanking point. It is fawn coloured, but the colour is more or less obscured by the carpet of algae with which the crab covers its carapace. The materials are held in place by hair-like projections from the body surface. In the drainage line in the centre of the island, and making deep burrows, is the Mangrove crab (Cardisoma carnifex). Although normally associated with mangroves, it is equally at home on the wet and muddy forest floor.
ECOLOGICAL WEBMASTERS TERRESTRIAL INVERTEBRATES Terrestrial invertebrates are a very significant component of Cousine Island's ecosystem. The many species play important functional roles, including that of leaf and litter breakdown, nutrient recycling, pollination, as well as being food resources for the introduced Seychelles endemic birds and for the endemic skinks. The restoration programme has led to a major change on the Island's plain, with the development of a forest canopy and a leaf litter layer in only ten years or so. The invertebrates have responded according to their various habitat requirements, with the forest species increasing in abundance, while the sun-loving ones have declined. Nevertheless, there have been no invertebrate extinctions on the Island. One of the reasons for this is that on the south-eastern and north-eastern corners of the island there are still relatively extensive areas of open habitat which provide the sunlit conditions necessary for some of these species. Furthermore, the introduced tortoises also play a role in maintaining open habitats, at least at the forest margins. We now consider the various invertebrate taxa in turn, and comment on their response to the Island's restoration programme.
Land snails Only two land snails have been recorded on Cousine. One, the Red achatina (Achatina fulica), was introduced into the Seychelles from Africa, but now appears to have died out on Cousine, as only old shells now occur scattered over the Island. The local Seychellois confirm that no live animals exist, and it appears that the dry spells to which the Island is occasionally subject are of sufficient duration to kill Red achatinas. This may be associated with changes in regional rainfall patterns in the late twentieth and early twenty-first centuries, which appear to have caused the extinction of the Aldabran endemic snail Rhachistia aldabrae (Gerlach 2007). The other land snail on the Island, the pan-tropical Spiral shell (Subulina octona), is fairly common in loose soil, under and in leaf litter, and under stones and logs in windsheltered or damper areas.
The shell remains of Red achatina snail about to lay eggs (seen as small balls inside the shell). This introduced species has since died out on Cousine.
Earthworms An earthworm species occurring in the drainage line is the Tropical earthworm (Eudrilus eugeniae) which is common in the hydromorphic soils (soils formed under wet conditions). It has also been recorded from Mahé and is known from many tropical, sub-tropical and some temperate areas. A second, smaller species is the Broom earthworm (Pontoscolex corethrurus), which is widespread over the Island in soil under litter in damper, protected areas, usually in the top 40 mm of soil. It originally came from the tropical forests of northeast South America and has now been recorded in many tropical and sub-tropical countries, especially in agricultural soils. The species is known to be tolerant of saline and polluted conditions and has also been recorded from Mahé and Praslin. The Log earthworm (Dichogaster affinis) lives in rotting tree trunks (including those of Coconut, Balfour's pandanus and Pisonia). It occurs in various parts of the tropics and sub-tropics but is so far only known in the Seychelles from Cousine, where it contributes to the decomposition of logs. Although not closely related to earthworms, it is worth noting that no leeches have ever been found on Cousine, possibly due to its relative dryness.
Tropical Island Recovery: Cousine Island, Seychelles.1st edition. By Michael Samways, Peter Hitchins, Orty Bourquin, and Jock Henwood. Published 2010 by Blackwell Publishing Ltd.
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Spiders, ticks and allies
Spiders
Pseudoscorpions
Eighteen families and 46 species of spiders, including four new species and a new genus (Cousinea), have so far been found on Cousine (Saaristo 1999). Most are small species, but there are two exceptions. On both flatland and in coastal granite areas, the large, multiple webs of the Palm spider (Nephila inaurata) can be seen. The species is not common on Cousine and numbers appear to fluctuate. Other spiders use the webs of the Palm spider to support web strands on their own, while spiders which steal food caught in the Palm spiders web (kleptoparasites) may also be present.
These are tiny animals, no more than a few millimeters long, and look like scorpions except that their tails are not elongated. They do not carry a poisonous sting. They are active, fast moving creatures and hunt and feed on small invertebrates. Apart from being under loose bark of trees on the flatland, they are also known from the granites, especially in litter under Pisonia forest. They have even been found in the untidy stick nest of an Indian mynah. The only species so far recorded in this group is the Slow pseudoscorpion (Withius piger).
Seychelles whip scorpion In the caves, cracks and crevices of the large granite boulders lives a fearsome looking but harmless member of the arachnids, a tailless Seychelles whip scorpion (Phrynichus scaber). The species is greatly flattened dorsoventrally, enabling it to enter narrow cracks for shelter and to capture its insect prey. It has front legs up to 180 mm long, which are modified into whip-like tactile organs. The second pair of legs is modified as grasping legs, up to 100 mm long, which are armed with spines and fold in like a jacknife. The species is endemic to the Seychelles granitic islands.
Seychelles whip scorpion. Closely related to whip scopions is a small group of arachnids known as schizomids. They are very cryptic and generally associated with woody leaf litter. Three species, all in the genus Schizomida, have so far been found on Cousine. They have increased in abundance with the restoration of the plain forest, especially as it has matured with woody material beginning to accumulate on the forest floor.
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The tough and conspicuous web of the Palm spider, with the small male on the left and the large femal on the right.
The female Palm spider is a formidable predator of larger, flying insects.
A large spider which is a free-ranging ground and wall dweller, and which frequently makes its way into buildings, is the Hunting crab spider (Heteropoda venatoria). The species has a conspicuous black mark on the front part of the body, with cream, grey and back patterning. The first long leg joints have clear blackringed pale dots. The body is about 23 mm long while legs are up to 60 mm long. A much smaller relative of the Palm spider is also a web-spinner, the Little orb spider (Drexelia bifida), which makes its somewhat untidy little web up to two meters above the ground in bushes and trees. It will also frequent house roofs. Star-legged spiders are small animals, often found in or around dwellings. They lie in star shaped mesh webs made over cracks, crevices and in corners of rocks and walls. Two species have been found on Cousine, one being new to science. Daddy-longleg spiders are delicate spiders with legs as much as four times longer than their bodies. The House daddy-longleg (Smeringopus pallidus) is common in cupboards and other hidden corners in the houses. The female carries the agglutinated mass of eggs in her chelicerae (jaws), unprotected by an enveloping cocoon, which is an unusual habit in spiders. The eggs, never numerous, may be as few as two. Four species of daddylonglegs are known from Cousine. The venom associated with their jaws is considered among the most potent biological substances known. However, their jaws are so tiny that they are not able to penetrate the human skin and are therefore not dangerous. Two species of Spitting spider have been collected. These spiders hunt by moving slowly in dark corners and immobilizing any prey found using a secreted poisonous sticky substance. The sticky secretion can be zig-zagged over the prey, like a net, pinning it to the ground. The Wall crab spiders or "flatties" are represented by the Secretive flattie (Selenops secretus). As the general name for the family implies, these spiders are extremely flattened, enabling them to shelter in narrow crevices in rocks, under bark and the like. They are agile, fastrunning animals, and their eggs are laid in disc-shaped flat white cocoon, attached to the substrate under shelter. Three species of Sac spiders, and two of the Flatbellied ground spiders, occur on Cousine. The Sac spiders are free-roaming, aggressive hunters which have a cytotoxic venom. Bites to humans can result in
which are slow to heal. Among the very small spiders (less than 3 mm long) are the Dwarf hunting spiders, which are nocturnal, ground dwelling spiders, the Spurred orb-weavers, and the Midget ground weavers. Members of the latter spin small irregular webs in deep litter in forests. Other litter dwellers are the Litter spiders, which are nocturnal and are medium sized (6 mm to 8 mm long). The Money spiders are sheet-web builders, making loose flattish webs with a scaffold of threads holding the web in place. They are small to very small (below 6 mm long). Members of the Cobweb spiders are known for their care of their broods. They feed the young on regurgitated substances until the spiderlings first moult. Some species will even catch food for their spiderlings. The Wolf spiders are represented on Cousine by two smallish species. These do not make webs but are freeranging ground hunters. The females carry the eggs in a silken pouch around with them until hatching takes place. Among the spiders most commonly seen are the Jumping spiders. Jumping spiders are common on the flatlands and enter houses to forage. These are the most speciose of all spider families, and are active, usually diurnal, animals and stalk and leap on their prey with great precision. In the great majority of jumping spiders, the front legs, which catch and hold the prey, are generally longer than the hind legs, which are used for jumping. Jumping spiders will also forage around lights at night. Six species have been identified from Cousine. Saaristo (2006) gives details of the cobweb spiders of the Seychelles.
Ticks and mites Mites and ticks are not common on Cousine, although 36 species have been found in leaf litter but not yet identified. Gerlach (1995) gives a key to the holothyrid mites of the Seychelles. A small orange red mite is found on Seychelles and Wright's skinks, usually in the armpits of the animals, and evidence of feather mites feeding on the feathers of some bird species has been seen. Two young ticks (Amblyomma loculosum) have been recorded on the legs of humans on the Island, as well as on the foot of a Seychelles magpie robin and on a young Sooty tern.
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These ticks are one of the two common tick species found on seabirds, whose deaths can result from viruses transmitted by the parasites. Up until 2003, few of these ticks were present on Cousine or its birds. However, after the natural recolonization of nesting Sooty terns in April 2003, the population level of ticks increased.
A Horn-eyed crab feeding on a Giant millipede wandering on the beach.
Engorged female tick on the foot of a Seychelles magpie robin.
Millipedes and centipedes Millipedes The most conspicuous representative of the group on Cousine is the Seychelles giant millipede (Seychelleptus seychellarum). It is endemic to the granitic Seychelles and occurs on Cousine, Cousin, La Digue, Silhouette, Félicité, Aride and Frégate (Gerlach 1997). It is very common on Cousine, being found in all terrestrial habitats, but very rarely on the beach and never in the intertidal zone, but preferring the wooded granitic areas. On most of the other islands it is scarce to very scarce.
Giant millipedes can grow up to 30 cm long.
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Following a census of the animals on Cousine, it was estimated that over a million individuals occur on the island, with a calculated weight of 1 773 kg per ha, or 46 100 kg in total (Lawrence and Samways 2003). The role of the millipede in litter breakdown is considerable. It ingests over 4.5 % of the litter standing crop, and consumes 17.2% of the daily litter fall every 24 hours. This makes the species an extremely important reducer of organic material, adding tons of rich manure to the Island and recycling nutrients in the Island's biological systems. The ratio of adult males to adult females is one to five, with immature millipedes making up about 20% of the total population. The animals tend to be much more active at night, and up to 20 times more millipedes forage during the night than during the day, when most shelter in rotting logs, under stones and litter, and in crevices and hollows in trees (Gerlach et al. 2005). Dead millipedes are fed on by skinks, crabs and a number of invertebrates, while live millipedes may be killed and eaten by the Seychelles magpie robin (Copsychus sechellarum), the Tan rock crab (Geograpsus crinipes) and the Dark ghost crab (Ocypode cordimana).
The Dark ghost crab is one of the major predators of the Seychelles giant millipede.
Other smaller millipede species, related to the Seychelles giant millipede, also occur on the Island. One, the Stripe-headed millipede (of uncertain identity) is a handsome red-brown colour and has red legs. It is usually associated with logs and has benefited from the logs left behind after the felling of Casuarina trees. Another millipede, the Long-stripe millipede (Dactylobolus bivirgatus) is rarely seen, but comes out after rain and may be seen foraging on damp rock surfaces, where it appears to feed on the litter accumulated in the crevices of the rock.
Millipedes are one group of invertebrates that has benefited enormously from the restoration of the coastal plain, having expanded their local range very rapidly into these re-afforested areas. The increased shade and leaf litter has created the damp microclimate that they prefer, as has the leaving of logs of alien plants left to rot under the new canopy. All the millipedes together are clearly important webmasters recycling the nutrients from the fallen plant material on the forest floor.
Centipedes The fearsome Red-legged centipede (Scolopendra subspinipes) (Lewis 2007) is up to 15 cm long, and occurs in coarse debris and in rock piles. It hunts at night along paths or around buildings. The bite is extremely painful, but not fatal. Its body colour varies from dark reddish brown to yellow, with green edging to each segment. The legs are pale red brown.
The Striped-headed millipede.
A large, expired Red-legged centipede having been attacked by a Wright's skink.
A group of Long-stripe millipedes and a Seychelles giant millipede foraging on a damp rock surface. Keeled millipedes are represented on Cousine by at least two small species, both found as litter dwellers under tree cover. The animals have slightly flattened bodies with 20 body segments with lateral keels. These keeled millipedes do not have eyes.
The Blue-legged centipede (Otostigmus rugulosus) is widespread and common in rotting tree trunks, leaf litter, under rocks and under loose bark. It is a mediumsized species, up to 65 mm long, with a grey to greenblue body and grey-blue legs. Earth centipedes are slender, elongate and wormlike, with 39 to 128 body segments and pairs of legs. They do not have eyes, and the antennae always have 14 segments. They usually live a subterranean existence but in semi-arid regions are also found under stones and the bark of trees. Three earth centipedes (Mecistocephalus spp. and the endemic Nesogeophilus leptochilus) are common, whitish and live in litter in Ficus-Pisonia woodland, and in rotting Coconut trunks. They have become much more abundant on Cousine with the restoration of the plain forest.
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Stone-centipedes are only 8-10 mm long. They have 15 pairs of legs, which are long and slender. One species (Lamycetes sp.) occurs in forest litter. Gerlach (1997) gives an introductory key to some of the Seychelles millipedes and centipedes
Insects Damselflies and dragonflies To date, 19 species of damselfly and dragonfly have been recorded in the Seychelles, and eight of these have been recorded on Cousine. Since 1997, when the artificial ponds were no longer cleaned, a number of species started to breed on the Island (Samways 1998b, 2003a). During dry spells, dragonflies become scarce and may even be absent. Since many are strong fliers, or can ride wind currents, they can easily cross the few kilometers of sea between Cousine and the neighbouring islands of Cousin and Praslin. The single damselfly species on Cousine is the Common citril (Ceriagron glabrum) which appeared at the tortoise baths in 1997. It is small, with the males having a bright orange-brown body and the females being a little duller.
The Common citril, although delicate in form, is an excellent colonizer. It readily colonized Cousine when the tortoise pools were installed, but has since declined as the pools have become shaded with formation of the tree canopy. The largest dragonfly seen on Cousine is the Amberwing emperor (Anax guttatus), which is a visitor that hawks over the open areas of the coastal plain. It is a striking animal with green eyes and
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thorax, a fawn abdomen with green spots, a bright blue patch on the dorsal base of the abdomen and a round, yellowy cloudy spot on each hindwing. The Vagrant emperor (Anax ephippiger), another large and conspicuous insect, is yellow-brown with a bright blue basal abdominal segment and the hind wing has central and basal yellow patches. As the name implies, it is a great wanderer. On 6 November 1996, at day break, a swarm of Vagrant emperors arrived on the Island. They appeared following strong southeasterly winds during the night, but were mostly gone within a week, although a few remained for the next two months. The Twister (Tholymis tillarga) is a fast flier often seen patrolling ponds in the late afternoon. Pairs whirl in circles over the water, sometimes joined in these aerobatics by one or more individuals. Its body is fawn to bright red, with a conspicuous clouded dark brown patch flanked by white in the centre of the hindwing.
The Twister, aptly-named from its rapid, twisting flight. It can look ghostly at night, with its dark brown and black wings flapping fast, low over the water. This species soon colonized the sunny tortoise pools when they were built, but is now scarce on Cousine as the restored trees have shaded out the pools. One of the most widely distributed dragonflies in the world is the cosmopolitan Pantala (Pantala flavescens), usually seen between November and April. The body is an orange- brown, and the wings have a faint yellow clouding on their tips. This species breeds on the Island, even in the tiny small bird baths, which can become tepid from the hot sunshine.
It is remarkable how they survive these warm conditions. The larvae are highly cannibalistic, and although a small pool starts with several larvae, it usually ends up with a single, well-fed one.
Pantala, also appropriately known as the Globe Skimmer, is well able to reach every tropical island, including Cousine. It is the only species to have colonized the world's most remote island, Easter Island in the Pacific. The Continental glider (Tramea limbata) is another great wanderer. The males have dark red bodies and a dark reddish brown patch at the base of the hindwing. The females are yellowy-brown with smoky yellowish patches on the wings. Both males and females whirl and glide in forest openings and tree margins, often in company with Pantala.
The only Seychelles endemic dragonfly, but only at the subspecies level, on Cousine is the Seychelles skimmer (Orthetrum stemmale wrightii) with its distinctive pale blue body and black diagonal markings. This is a perching dragonfly, often seen on a twig in a shaft of sunlight by a pond, actively moving its head back and forth, and ready to dart and catch a passing
The Seychelles skimmer is very shade tolerant. It has benefited from the restoration of the coastal forest around the tortoise pools, where it perches, often darting out over the pool to catch insect prey flying past. The smallest dragonfly on Cousine is the small Blue Percher (Diplacodes trivialis). Males have slender light blue bodies. This alert little dragonfly is very fond of the tortoise baths, where it displays its perky perching behaviour, darting out to defend its territory or to catch a small flying insect that strays past its perch. Since the development of the tree cover on the coastal plain and the shading of most of the tortoise baths, the Common citril, Twister and Blue percher are no longer common residents, as they require sunlit pools. Pantala, Twister and Continental glider still breed as they can do so in the surprisingly small and warm bird baths. The Seychelles skimmer is shade tolerant and still breeds on Cousine.
The Continental glider, a master of the air, easily shuttling from one island to another.
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The Blue Percher is an alert little dragonfly. Although it can be common around sunlit tortoise pools, it will not visit those in the shade, and so it has decreased on Cousine in recent years.
Crickets and grasshoppers Crickets and grasshopper comprise many families and species, but are few in species on Cousine (Gerlach and Haas 2008). The Entreating cricket (Gryllodes supplicans) is associated with the cultivated area and buildings. It forages at night and adds to the night sounds with its gentle, trill-like calls. On the undersides of leaves of many of the trees is a tiny bright green cricket, the Darting green tree cricket (Pteronemobius sp. cf tapobranensis), which will rapidly dart away as the leaf is turned over. It is common on all the large-leaved trees, and it has benefitted enormously from the restoration programme, now being widespread across the island in all forested habitats. The Zanzibar grasshopper (Jasomenia sansibara) is the only grasshopper species so far found on Cousine, where it is common in open grassy areas. Its range on Cousine has retracted where the Pisonia forest has established on the coastal plain. Nevertheless, its habitat is improved by tortoise grazing, which inevitably takes place mostly in sunlit grassy and herbaceous patches in forest clearings.
The tiny Zanzibar grasshopper, characteristic of the open, grassy and herbaceous areas of Cousine. While it has been reduced on the plain, with succession from grass and mixed herbs to forest, it has increased in the grassy areas where Coromandel has been cleared. A number of bush crickets, characterized by long slender antennae and long curved ovipositors on the females, have been found coming to lights at night and in open areas and most kinds of vegetation. Those on Cousine are usually plain green or brown in colour, the most abundant of which is the Common ruspolia (Ruspolia differens).
Common ruspolia.
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Males of bush crickets have a stridulatory apparatus on their wings with which they produce their strong, buzzing, nocturnal calls. Matyot (1998) gives an overview of the threats to the orthopteroids of the Seychelles. In 2008, a remarkable cricket, Alluaud's spider cricket (Phalangacris alluaudi), was discovered in the dark recesses of deep rock overhangs. It has antennae up to 18 cm long, which can be extended both fully forwards and backwards, enabling it to scan a 36-cm diameter circle in the darkness. Individuals are spaced apart but keep in touch with these long antennae.
Even the young of this Alluaud's spider cricket have extraordinarily long antennae.
Earwigs Earwigs are usually nocturnal, spending the day in debris, under bark and in other protected situations, particularly in moist situations. They are chiefly plant feeders or scavengers, but some are predators of small invertebrates which they capture with their forceps. The Ringlegged earwig (Euborellia annulipes) is a cosmopolitan insect occurring in a wide range of habitats, including fig forest litter, where another introduced European earwig (Labia minor), which has surprisingly good powers of flight, also occurs. Earwigs have become much more abundant on Cousine in recent years, having colonized the leaf litter under the restored forest canopy on the plain. Alluaud's spider cricket has remarkably long antennae, which can be bent around and backwards, enabling it to scan a 36-cm diameter circle in the darkness of rock overhangs. It maintains contact with other individuals by touching antennae, seen here as the fine downward-pointing line in the middle left of the picture
Cockroaches Among the forest litter, under rocks and under logs is a very common little animal about 20 mm long, the Indian cockroach (Pycnoscelus indicus) (Kelly and Samways 2003). Males are winged, while females and subadults are wingless. Wingless individuals are black, while the adult males have black heads and strawcoloured wings and legs. It is an introduced species, common in chicken runs in India, and relished as a food item by a number of bird, lizard and invertebrate predators such as the Seychelles magpie robin (LeMaitre 2002), Seychelles skink and centipedes. This is an unusual situation where an invasive alien species is actually contributing to the conservation of rare and threatened species. As it thrives under forest trees, it has increased in numbers and expanded across the coastal plain wherever trees have developed a dense canopy.
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It is also benefiting from the old Casuarina logs which have been left under the newly-established indigenous tree canopy. This, in turn, has provided more food resources for the Seychelles magpie robin, which now commonly forages in this coastal forest.
The Indian cockroach, an important food item for the Seychelles magpie robin, even though it is alien. An insect which was first found on Cousine during November 1996, originating out of packages from South Africa, which is a common house pest in many parts of the world, is the large, blackish American cockroach (Periplaneta americana). It was immediately eliminated, and was not seen again until 2001 when it arrived in a suitcase from Praslin Island. Whenever it is seen, it is eradicated, although evidence so far suggests that this species is limited to dwelling areas and may not become invasive over the whole island.
Termites It is believed that all termites in the Seychelles are either Indian or Pacific species distributed through human agency. Indeed, wherever there are large trees on the Island, especially Coconut, termites construct brownish-black, earthen tunnels which meander up tree trunks, and at intervals, form a large nest. These nests are usually on the sheltered side of the tree. These are the nests and tunnels of the Black snouted termite (Nasutitermes nigritus). The soldiers are blind, and have large, shiny red-brown heads ending in a beak-like snout. Workers have no snouts and are larger. The nests are also homes to the Termite click beetle, whose association with the termites, apart from living in the nests, is not known. This beetle flies to locate new termite nests, and while doing so, may be distracted and attracted to lights. There are two other species of termite on Cousine, Scott's termite (Calotermes scotti) and the Slopingface termite (Arrhinotermes calanifrons). The increased size of the forest cover has greatly benefited the termites, which now occur under the canopy of the established trees on the coastal plain.
Tunnels and a nest of the Black snouted termite on fig tree trunk.
American cockroach, a potential pest on Cousine kept in check by fierce competition for food.
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Bugs, cicadas, aphids and scale insects Shield bugs are mostly medium to large (up to 30 mm long) bugs which usually have well-developed stink glands. They are primarily day-living and feed on plants. The largest of the two species so far found on Cousine is the Green shield bug (Nezara viridula), which is a pest of vegetables throughout the tropics. It is bright green in colour, although avoided by birds as a food item owing to its bad taste.
Green shield bug. The edges of young leaves of Takamaka and Pisonia trees are often found rolled up, and caused by a small homopteran insect known as a mealybug, of uncertain identity. Like most members of its family, its body is covered by a white, waxy secretion, which looks like maize flour. The rolled-up leaves attract bees, ants and the Seychelles sunbird because of a sweet substance, called honeydew, which is excess sugar intake from the plant juices excreted by the mealybugs. The female is always wingless, has a fused head, thorax and abdomen, and also may be legless. She functions virtually as a container for developing eggs. Males in contrast are completely formed and very small, yet fly well to seek the sedentary females. Other homopteran insects that occur on Cousine, include the Pulvinaria scale, which is particularly common on Pisonia, and also excretes honeydew. This scale is usually seen as a brown disc with a white waxy extension, which is the egg sac. Ants are very fond of the sweet honeydew. In return, the ants protect the mealybug or scale insect from attack by parasitic wasps and predators, such as ladybirds. This mutualistic relationship results in large outbreaks of both homopteran and ants, occasionally leading to Pisonia tree death.
The Seychelles cottony cushion scale (Icerya seychellarum) (Hill and Blackmore 1980), despite its name, is not endemic to the Seychelles, and commonly occurs on figs. The large populations of this cottony scale on the side shoots of fig trees have become a favoured food of the introduced Seychelles white-eye, which has taken to avidly foraging in the fig forest.
The Seychelles cottony cushion scale being attended by worker Big-headed ants which are collecting sweet honeydew excretions from it. This scale insect is an important food item for the Seychelles whiteeye. Another homopteran insect which is often seen on Morinda is an aphid, of uncertain identity, which produces copious amounts of honeydew on the surface of the leaf. This sugary substrate then acts as a substrate for colonizing black sooty mould.
A minute aphis occurs on Morinda, where it excretes sugary honeydew which turns black as it is colonized by sooty mould.
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An unusual little delphacid homopteran, also of unknown identity, also occurs on Cousine. It is very sensitive to invasive effects of the Big-headed ant, and only occurs in any numbers where this invasive ant is in low numbers.
Males only have a curved horn on their head which they use in combat with each other for mating rights. Larvae develop in rotting vegetable matter such as decomposing coconut trunks. The species was introduced from West Africa, and is active at night.
This small delphacid homopteran, with distinctive tail plumes, and which is very sensitive to invasion by the Big-headed ant.
The aptly-named Rhinoceros beetle.
Antlions and lacewings The Yellow-banded antlion (Myrmeleon obscurus) is a small antlion, just over 25 mm long. The pterostigma (wing spot on the leading edge of each wing) is white, the head has black and yellow markings, and the abdomen is grey with yellow bands and up to 18 mm long. It occasionally comes to lights. As these species require very sunny habitats, they have, not surprisingly, decreased with the establishment of the coastal forest.
Beetles One of the most conspicuous beetles on Cousine is the Eyed ground beetle (Chlaenius bisignatus), up to 2 cm long, black with two, big brown spots. It is a predator of smaller insects. The scarabs include the well-known dung beetles, rhinoceros beetles and lawn chafers. The largest (40 50 mm long) beetle on Cousine is the Rhinoceros beetle (Oryctes monoceros). Adults feed on developing Coconut leaves, and where the beetles are common they can cause considerable damage to the trees.
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Rhinoceros beetle damage to a coconut palm trunk.
The Sedge beetle (Rhisotrogus sp.) is 11 - 15 mm long, and has a glossy black thorax and glossy bronze elytra. The hind legs are longer than the total head and body length. Although primarily seen coming to lights at night, it has been found on a common sedge (Mariscus ligularis) at night. The Flower scarab (Protaetia aurichalcea) has a characteristic lichen-like appearance, which camouflages it when at rest on the trunks of trees. It has increased in abundance on Cousine since establishment of the coastal forest.
Ladybirds are small, rounded beetles, of which most species larvae and adults prey on aphids and their allies. Some feed on plants and can become agricultural pests. The Shiny black ladybird (Chilocorus nigritus) is polished, shiny black, with an orange face mask. It is common on Cousine, and has been found on a number of plant species, where it feeds on scale insects (Samways 1998a). The species was introduced to the Seychelles during 1938, when 40 were brought in as a start in controlling scale insects on coconut palms. It did this successfully within five years, and continues to control these scale insects. It is a very opportunistic feeder, rapidly laying eggs in the vicinity of scale insects where the Big-headed ant has been excluded. Gerlach (1999) and Matyot (1996) give keys to the Seychelles chrysomelid and buprestid beetles respectively.
The Sedge beetle
The Flower scarab has increased in abundance with establishment of the coastal forest. The Terminalia beetle (Adoretes versutus), like the Sedge beetle, is a chafer, and can be found at night on Pacific almond trees (Terminalia catappa), where it feeds on the undersurface of the leaves. It is 10 – 12 mm long, has a blackish brown thorax and dark brown elytra, and the body is covered with short, inconspicuous white hairs. It has benefited from the restoration of the forest and growth of the Pacific almond trees.
The Shiny black ladybird, originally introduced into the Seychelles to control scale insects on coconuts, which it did most successfully.
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Flies The flies of Cousine are poorly known, although Kelly and Samways (2003) record Nereius alluaudi, Monogoma pennipes and Mydaea compressipalpis, as well as several unidentified species. Some recent publications on flies of the Seychelles include Spungis (2006), Menzel and Smith (2007), Meuffels and Grootaert (2007), Verves (2007) and Cariou et al. (2008). Mosquitoes are delicate narrow-winged flies with piercing and sucking mouthparts. Eggs are laid on water or on moist substrates and larval/pupal development takes place in water. One species, the Single-striped mosquito (Aedes unilineatus), a voracious blood feeder on humans, is common on Cousine. It is widespread throughout Africa, and is most active in shaded areas during mornings and evenings. Its bite raises welts out of proportion to its small size. The same species also harries the giant tortoises, being most noticeable around the heads of the animals. Fortunately none of the mosquitoes on Cousine have yet been identified as vectors of any parasites causing diseases in humans. Members of the genus Aedes lay their eggs singly on a moist substrate, and providing there is enough humidity, they can survive for long periods, even years. Hatching takes place after rains, via a mechanism called installment hatching, where some of the eggs hatch after the first submersion, some after the second submersion, and so on. It is an efficient survival strategy. Deoxygenated water is needed for good hatching, so that water with oxygen-using bacteria, yeasts and protozoans is ideal. Breeding on Cousine takes place in containers standing in the open, tree-holes and other natural water-traps. In 2008, about 60 individuals of the Playfair' s panchax (killifish) (Pachypanchax playfairi), a small indigenous fish which is a predator of mosquito larvae, as well as other invertebrates, were introduced into the tortoise ponds. Initial results indicate that the fish are reducing the population levels of the mosquitoes in the ponds.
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Another group of flies which can pester humans are the horse flies. They are relatively stout-bodied, medium to large (10-25 mm) flies. The adults of both sexes feed on the nectar and pollen of flowers, but the females of most species have piercing mandibles and also suck blood, mainly on mammals (including humans). The larvae usually live in wet places such as mud or damp soil. One species, the Turtle tabanid (Neavella albipectus), feeds on the blood of nesting turtles. They do not shirk at trying human blood and can deliver a painful bite. The species is a dark brown colour with pale margins on its abdominal segments, giving it a banded appearance. It is diurnal, appearing during the Hawksbill turtle nesting season and is most active during hot weather.
The Turtle tabanid, sucking blood from an area of soft skin on a nesting turtle. Robber flies are carnivorous, feeding on living prey, especially other insects, which they catch in flight. The larvae live in soil or in burrows in wood. One small, grey species (Clinopogon nicobarensis) is common on the beach, where it flies fast and low, settling after a short flight, and flying off again on being disturbed. An interesting group of flies are the louseflies. They are blood sucking parasites of mammals and birds. Females are viviparous and give birth to one maggot just before it pupates. One shiny black species, the black louse fly comes to lights during November to January, when the Seychelles fruit bats fly to Cousine to feed on the figs and other fruit. It is probable that this louse fly is associated with these bats.
The adults appear over a few days in large numbers, or peak in numbers over a few weeks. They may be seen flying for between a week and a month and a half before disappearing, and have been recorded in the months December-January and March-April.
The Black lousefly.
Butterflies and moths It is not certain whether the butterflies are permanent residents on the small islands. If so, then mass synchronized hatching of the pupae following required climatic conditions must be taking place. The rainfall for Cousine is highest during January and February, immediately preceding the butterflies' appearance, but when unseasonally high rains occur, the butterflies may appear during mid-summer, indicating flexibility in adapting to favourable rainfall conditions. It seems that rainfall spurs food-plant growth rates, leading to good conditions for larval growth, and triggering mass adult emergence from the pupae. The butterflies are therefore considered to be permanent residents on the islands (Bourquin et al. 2000, Lawrence 2005, Gerlach and Matyot 2006)). As such, it would be interesting to see if any genetic traits have developed for individual islands.
Butterflies The Common diadem (Hypolimnas misippus) is widely distributed through the Afrotropical region and in the Seychelles. Its food plants include Coromandel and Fleshy portulaca. Both the food plants are common and widespread on Cousine Island. The male is black with two oblique elongated white spots on each forewing, and a large white spot on the hindwing. The female is orange with black and white patterns on the wings, much resembling an African monarch (Danaus chrysippus), and for which it is often mistaken. The females have at least two colour patterns, varying in the degree of black and white markings.
The Common diadem, seen here mating, is an occasional visitor to Cousine. The male and female are very different in colouration, the male being black and white, and the female mostly orange. The Painted lady (Vanessa cardui) is a widespread butterfly throughout much of the world, and is an occasional visitor to Cousine. It is a powerful flier and has a wide host range, making it a prime opportunist and generalist. The tiny Lucerne blue (Lampides boeticus) is widespread in Africa and extends into Europe and most of the warmer parts of the East. It is occasionally seen on Cousine, where it feeds on various legumes. The African grass blue (Zizeeria knysna) is a widespread African species that is a common and permanent inhabitant on the open flat areas of Cousine, flying around low growing plants during all months of the year. Known food plants include Amaranthus and Euphorbia, both genera being well represented on Cousine. It has decreased in abundance as the Pisonia forest has established and shaded out its habitat. It is confined now to the sunlit forest gaps where the tortoises graze and maintain suitable habitat for it.
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The Variegated night moth (Achaea catella) is an occasional night visitor to lights. This moderately sized moth (wingspan to 65 mm) is attractively marked in cream, brown and tan.
Wasps, bees and ants Parasitic wasps
The tiny African Grass Blue, which benefits from tortoise grazing. The Olive-haired skipper (Borbo borbonica) is widespread in Africa, and the Indian Ocean islands, although scarce on Cousine (Lawrence 2006). It has been observed from October to April flying swiftly, usually along the edge of Fig-Pisonia forest and open areas. It is dark brown with a row of white spots across the forewing. The food plants include various grasses.
Moths Many small moth species have been recorded on Cousine, especially around lights at night. Among the large moths, the Convolvulus hawk moth (Agrius convolvuli) is the largest recorded so far on Cousine, with a wingspan of 95 mm. The wings are variegated brown and cream and the abdomen is banded yellow-brown and black. At the base of the thorax red, black and white marks form a conspicuous patch when the hindwings are lifted. It is a rare visitor, seen hovering expertly in front of flowers at night, and probing them with its 100 mm-long proboscis. Matyot (2005) and Spungis (2006) give keys to the Seychelles hawkmoths.
The Convolvulus hawk, hovering and expertly extracting nectar from a flower at night.
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Six families of wasps have been recorded on Cousine. The ichneumon wasps are parasitoids which feed on larvae and pupae of many insects, as well as on some spiders. Braconid wasps are parasitoids like ichneumons, but are all generally small species. Representatives are an Apanteles sp., which parasitises butterfly and moth caterpillars on the Island. Fig wasps live mainly in the figs of fig trees (Ficus sp.), and act as pollinators as well as parasitizing the fig fruits. The males and females differ in appearance, the females are usually small (about 1mm) and are
Vespid wasps The vespids are the familiar wasps, and are generally medium-sized to large (up to 35 mm long), and are usually patterned in warning (aposematic) colours, yellow or red and black. They are social animals and build paper nests made out of chewed plant fibers. The Yellow wasp (Polistes olivaceus) is common on the Island. As it stings fiercely, it should be treated with respect.
The Yellow wasp, being an open habitat species, has declined on Cousine with restoration of the plain canopy.
Most species of mason wasps are partly black with specific areas of the body being reddish-brown, orange, yellow or white. They are generally solitary species. Mason wasps build nests in holes in the ground or in hollow stems, or build mud nests. Three species are known from Cousine. A common wasp of the open areas, particularly on the coastal plain, is the Seychelles wood wasp (Odynerus seychellensis). They live in holes in tree trunks, where they store paralyzed caterpillars as a food store for their growing larva.
The Carpenter bees are represented on Cousine by the Afrotropical carpenter bee (Xylocopa caffra). This fairly common species starts its foraging during warm early mornings, often at daybreak. The females are black with two prominent yellow bands around the abdomen, while the males, which are infrequently seen, are golden yellow. Carpenter bees bore into wood, making nests in which they lay their eggs. It has decreased in abundance on Cousine with the extension of the Pisonia forest, but is still a common sight around the forest margins, moving from one flower to another in the sunny areas.
The Seychelles wood wasp. Alluaud's potter wasp (Eumenes alluaudi) is a common large wasp to 23 mm long, often making its characteristic mud nests in buildings. Butterfly and moth caterpillars are paralyzed and put into the nest, into which the egg or eggs are laid. The wasp larvae feed on the caterpillars. The larvae coat the inside of the nest with a silk layer blocking the nest hole once there is sufficient food in the nest. Two potter wasp nests were found to contain 12 caterpillars, one wasp egg, and two wasp larvae in different stages of development, and 13 caterpillars and one wasp larva, respectively
Bees The bees are represented on Cousine by two conspicuous species and several smaller ones. Both conspicuous species forage in open areas and on and in forest canopies, using a wide variety of food plants from which they extract nectar and pollen.
The sun-loving African carpenter bee, frequently seen visiting flowers in the patches between the trees. The long-tongued bees are generally small (2 mm to 6 mm long), with the exception of the Unicolour honeybee (Apis unicolor), which is common on Cousine. The honeybee forages in the open areas and on flowers in the forest canopy or on tall trees, such as coconut palms. As with many other bee species, it pollinates flowers, thereby ensuring viable seed stock for plant regeneration. The bee's colour can vary from a brown and yellow-banded abdomen to a virtually plain black abdomen. Natural hives can be found among granite boulders well covered with Beach morning glory and other herbs. The hive entrance is a crevice just above ground level.
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rich areas. The soldiers have massive heads and are larger (4 mm) than the workers (2.5 mm) and have more massive jaws and thoraxes. The head and abdomen are shiny and blackish, while the rest of the body and legs are reddish brown.
The Unicolour honeybee on Cousine, as the dominant pollinator, maintains many of the flower species, both indigenous and alien, on the Island.
Ants These are a very common insect on Cousine (Kelly and Samways 2003), although most are alien. The most primitive ants are the ponerines, and a common inhabitant of the Pisonia and Fig forest floor is the Black ponerine ant (Odontomachus troglodytes), which is a large (11-12 mm long) and shiny black, with a sting. Colonies nest in and under rotting logs, and have rapidly colonized the regenerating forest on the plain.
The Black ponerine ant which has colonized the newly forested areas on the plain The Big-headed ant (Pheidole megacephala), originally from Africa (Samways 1983), is a ubiquitous species on the Island, foraging in houses, on the ground, in granite areas, on trees and on the beach. It is not abundant in the deeply-shaded, litter-
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The Big-headed ant gathering to drink water The Big-headed ant attends the Seychelles cottony scale (a homopteran), causing localized outbreaks (Hill and Blackmore 1980), leading to twig dieback and occasionally even Pisonia tree death. The ant does this to obtain sugary excretions from its homopteran mutualist. In turn, the homopteran obtains protection from parasitoids and predators. Interestingly, there is a trade off on Cousine for having this scale outbreak: the scale is a highly favoured food of the Seychelles whiteeye. The ant also attends other homopteran insects such as Pulvinaria scale, mealybug and Soft brown scale, leading to loss of leaves and finally to twig dieback as in the case of the cottony scale. This ant can be in such abundance that it forages in the trees in many thousands to attend the homopteran mutualists, with the result that much honeydew is produced, much of which showers down onto the tree trunk. As it is sugary, it becomes an excellent medium for black sooty mould.
Severe twig dieback caused by the Big-headed ant stimulating an outbreak of Seychelles cottony scale
Mealybug outbreaks on Pisonia shoots and leaves, stimulated by the Big-headed ant.
Pulvinaria scale causing Pisonia leaf distortion and loss as a result of being attened by the Big-headed ant.
This is also Pulvinaria scale being attended by the Big-headed ant but it has not yet developed the long white waxy egg sac.
Sooty mould on a Pisonia trunk, incubating on the sugary honeydew excretion from homopteran mutualists with the Big-headed ant.
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The Big-headed ant has increased in numbers and extent with development of the coastal Pisonia forest. It plays a significant ecological role in scavenging the remains of organisms that have died in the forest, and therefore contributes to soil formation. However, there is concern that the restored forest, being dark and damp, and a favoured habitat for it, is encouraging it to reach pest proportions. Although small in size, it is an extraordinarily competitive ant, which can push out other ant species (Samways 1983: Hoffman et al.1999; Dejean et al. 2007) and dominate many interactions in the local ecosystem. It has been implicated in Hawaii for having had a major impact on local arthropod species (Zimmerman 1970; Gillespie and Riemer 1993). Big-headed ant nests are indicated by numerous burrow entrances and low mounds of excavated soil. Where leaves have fallen on the sand, these are used by the ants as a matted covering for their trails, the location of which can be readily found by looking for rough lines of dried needles. There are probably many millions of these ants on Cousine, and their impact on some of the prey species, and on the animals which use the same food items, must be enormous. The size of their own graveyards is testament to this large population.
Trail of the Big-headed ant: testament to it being a keystone species in the local ecosystem and having a great influence on general insect diversity.
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An enormous Big-headed ant graveyard, made up of its own dead and that of its prey. These ants are very hygienic and are continually cleaning out their nests, resulting in an accumulation of sometimes mounds of dead bodies. The species is a widespread pest throughout islands of the Pacific. Together with several other species, including the Little crazy ant (see below), it may be responsible for reducing invertebrate numbers on Cousine. This, in turn, could have an impact on the threatened, endemic land birds. Considerations are currently being given to localized control of this ant on Cousine. In Kakadu National Park, Australia (Hill and O'Connor 2004) the ant was locally eradicated using the proprietry bait Amdro, which has hydramethylnon as the active ingredient (Samways 1985). Such an eradication programme has much greater risks on the small island of Cousine, with its rich endemic fauna. While the bait is considered safe for vertebrates, there is concern for the Seychelles giant millipede which eats the bait. While no mortality of the millipede has yet been recorded, there may, nevertheless, be some sublethal debilitating effect on the millipede which could pose a risk. The Little crazy ant (Paratrechina longicornis) is widespread on the coastal plain, especially near buildings. It is dark brown to black and is covered with white and grey hairs. The legs are very pale. The legs and antennae are very long, both being individually longer than the length of head and body combined. The species is found in many parts of the world and is termed a tramp species, transported by humans.
Two ant species, both commonly found in houses, but also occurring in the garden area are the Little ubiquitous brown ant (Technomyrmex albipes) and the Transparent house ant (Tapinoma melanocephalum). The Little ubiquitous brown ant is small (3.5 mm long), dark brown, and with light brown antennae and legs. The antennae are shorter than their combined head and body length. Short hairs cover parts of head and body. The Transparent house ant is a very small (only 1.8-1.9 mm long) ant and an extremely swift runner. The abdomen and legs are a pale yellow, while the head and thorax are black. The antennae are yellow and are shorter than head and body length combined. The species is common in houses and is an introduced alien. Fortunately, to date, the Crazy ant (Anoplolepis gracilipes), which is such a pest elsewhere in the Seychelles (Hill et al. 2003), has not been recorded on Cousine. Gerlach (1998) gives a key to many of the ants in the Seychelles, and there is a Seychelles ants website (Fisher and Snelling 2008).
Isopods We met this group of crustaceans earlier, but in that case as inhabitants of the sea. We now consider them as forest floor dwelling animals, commonly known as 'woodlice'. Four species have been found on Cousine, and all are small and cryptic, living in leaf litter and in rotting logs. As they are very intolerant of dry conditions, it is not surprising that they have benefited enormously from the restoration programme on Cousine. Today, they are commonly found in the forest on the plain, an area where they were rare prior to the establishment of the indigenous trees.
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A RICH TAPESTRY OF FISH LIFE Seychelles fishes
Sharks, allies, and attacks on turtles
The marine fishes around Cousine are a colourful testament to its contribution in maintaining marine biodiversity. About 880 species are known from the Seychelles, and although most of these (about 96 %) are found in other areas of the world, the islands form various habitats allowing non-pelagic and shallowwater species to establish and flourish. Of the Seychelles endemics, three, the Seychelles anemonefish, Seychelles squirrelfish and the Seychelles soldierfish, occur around Cousine. Most of the fishes around Cousine can be identified using Lieske and Myers (2001).
Members of the cartilaginous fishes found around Cousine include occasional sightings of the largest of all living fishes, the Whale shark (Rhincodon typus). This reaches lengths of 12 m, and is a plankton and small fish feeder and is harmless to humans. The most dangerous is without doubt the Tiger shark (Galeocerdo cuvier), reaching lengths of up to 5.5 m. It is a predator of fish, including other sharks, and rays, turtles, seabirds, marine mammals and may attack humans. The illustrations below show two cases of shark attack on the Hawksbill turtle.
An array of fishes over coral rubble off Cousine.
A Hawksbill turtle showing the details of a shark bite with a large chunk of carapace, plastron and the left hind flipper removed from the left rear side. In spite of these injuries she still managed to complete at least some of her attempts at nesting.
Fishes are divided into two main groups. The sharks, skates and rays are cartilaginous fishes, characterised by having cartilaginous skeletons. They have no bony cover to the gill openings. The bony fishes, to which most of the fishes belong, have bony skeletons, and normally have a bony cover (operculum) over each gill opening. There are about 300 species around Cousine, but only the most important of these will be discussed here.
This Hawksbill turtle shows a similar shark bite but wider and exposing more of the soft body below. A portion of the left hind flipper has also been removed.
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Tropical Island Recovery: Cousine Island, Seychelles.1st edition. By Michael Samways, Peter Hitchins, Orty Bourquin, and Jock Henwood. Published 2010 by Blackwell Publishing Ltd.
Other sharks so far recorded are the Grey reef shark (Carcharhinus amblyrhynchos), Reef whitetip shark (Triaenodon obesus), Milk shark (Rhyzoprionodon acutus) and the Great hammerhead shark (Sphryna mokkaran). These are mainly fish eaters, with the smaller species feeding on octopuses and crustaceans as well. Fishes related to sharks are the guitarfishes, skates and rays. These are all flattened, and are usually bottom dwellers. The most common is the Spotted eagle ray (Aetobatus narinari), a graceful, swift swimmer which reaches widths of 2.5 m, and whose young are regularly seen in the inshore sea around Cousine. Characteristically, when swimming at the surface, the ends of their 'wings' curl up, and the tips, breaking water, look like shark's fins. Of great interest was a sighting of a Porcupine ray (Urogymnus asperrimus) covered with short spines. This is generally an uncommon species, even though it appears to be widely distributed in the Indo-Pacific region. A representative of the stingrays around Cousine is the Bluespotted ribbontail ray (Taeniura lymna) with handsome blue markings on its upper surface. It has a barbed, poisonous bony spine on the top of the tail. Some stingrays have caused human deaths when the spine has been stepped on or handled. As with most cases of poisoning involving fish spines or sea-urchin spines, the spines should be removed and the wound bathed or immersed in very hot water (to 55º C). This denatures the protein-based poison. Virtually all the skates and rays are bottom feeders, eating molluscs (especially bivalves), crustaceans and other sand-dwellers.
Diversity of bony fishes The bony fishes include the eels. To be treated with deference are the moray eels, as many of them have large, fang-like teeth, and if provoked will bite. Although the bites are not poisonous, considerable lacerations can result. Of the species around Cousine, the largest is the Giant moray (Gymnothorax javanicus), which can attain lengths of up to 3 m, and which feeds primarily on small fishes.
Giant moray - this one was 1.1 m long and weighed 4.25 kg.
A moray eel defending its coral rubble retreat. The Geometric moray (Siderea grisea) is easily recognizable because of the conspicuous, neat lines of black dots on a brown head. It inhabits, together with other larger eels, the coral and rock habitats in shallow water around the Island. Juveniles of this species and the Snowflake moray (Echidna nebulosa) may be found on the rubble flats at low tide, sheltering under rubble in small pools. Inshore and shallow-water predators include the 1.5 m elongated Houndfish (Tylosurus crocodilus) characterized by long narrow beak-like jaws with many needle-sharp teeth. It feeds primarily on small fishes, catching these sideways in its beak, and generally hunts in the upper meter of water. This fish has accidentally injured people on watercraft, with records of it jumping out of the water and hitting them with their pointed jaws. A similarly shaped, but much smaller (to about 25 cm) fish is the Insular halfbeak (Hyporhamphus affinis), a surface swimmer with a long lower beak projecting under a short upper lip. The prey is small plants and animals at the waters surface.
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Head of a Houndfish. The Cornetfish (Fistularia commersonii), while superficially resembling both needlefish and halfbeaks in shape, has an extended mouth shaped like a tube, which the Cornetfish uses to suck in small fish and crustaceans. It is often found slipping stealthily above shallow reefs, but can go as deep as 200 m below the surface.
The trevallys are generally not strongly toothed, and most have part of the lateral line marked by strong, ridged scales. The Giant trevally (Caranx ignobilis) is one of the few trevallys which has canine-like teeth in both its upper and lower jaws. It is a formidable predator and a prized game fish, reaching weights in excess of 50 kg. The Bluefin trevally (Caranx melampygus) can reach 100 cm in length and is seasonally common around Cousine, hunting close inshore during the evening.
The Bluefin trevally.
Cornetfish. Typical surface fish of tropical oceans are the flying fishes, which use their elongated, wing-like pectoral fins to glide through the air in attempts to escape attacking predators. At least two species occur around Cousine. Flying fishes feed on small pelagic animals, particularly crustaceans. Well known to anglers are several groups of fishes found around Cousine are the swift, sometimes large, gamefish. These include the group known as the trevallys, the tunas, mackerels and bonitos and the barracudas. These feed mainly on small fish and squid. The trevallys usually hunt in schools. A larger species, the Yellow-dotted trevally (Carangoides fulvoguttatus) attains a meter in length and up to 18 kg and goes to depths of 100 m, while smaller species such as the Bar-cheek trevally (Caranx plagiotaenia) (to 50 cm) and the Bigeye trevally (Caranx sexfasciatus) (to 85 cm) are associated with reefs. The Golden trevally (Gnathanodon speciosus) is also associated with reefs but unlike many other trevallys, it sucks up small prey (crustaceans and fish) from cracks in the reef and from seaweed.
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Often found over reefs is the Blackfin barracuda (Sphyraena qenie) with an elongated, handsomely black-barred body, and strong sharp teeth. The Eastern little tuna (Euthynnus affinis) and the Double-lined mackerel (Grammatorcynos bilineatus), usually hunt on shoaling surface fish, but will also hunt over reefs where fish of all kinds are eaten. The small surface-shoaling fish, which provide much of the food for carnivorous fish, sea-birds and, of course, humans, include groups such as herrings, sardines and pilchards, silversides and anchovies. Although representatives of all these families are well known from the Seychelles, few of the species around Cousine have been identified. Large shoals of these pelagic food fishes are seen frequently around the Island and in the shallows. Silversides are often found in very shallow water or along the edges of sheltering rocks, especially at night. One of the threadfin fishes (Polynemidae), the Sixfeeler threadfin (Polydactylus sexfiles) was seen attacking such a shoal of silversides. Threadfins resemble mullets (Mugilidae) but have three to eight long 'feelers', which are free rays of the pectoral fin, used for locating the small crustaceans and other bottom dwelling animals on which they feed, and a mouth in the undersurface of the head.
The mullets are detritus and algae feeders with a small mouth positioned at the end of the head. The common mullet around Cousine is the Fringelip mullet (Crenimugil crenilabrus) with prominent papilla along its lips. It can reach lengths of 50 cm, and is normally seen in small shoals foraging on rocks and reefs. One large fringelip was seen with a Sharksucker (Echeneis naucrates) attached to it. The Sharksucker's head is flattened on top and has a laminated adhesive disc which it uses to attach itself on a variety of hosts, usually large sharks. The Sharksucker feeds on small pieces of fish left by its carnivorous hosts and will also feed on the faeces of its host. The greatest variety of fish, and the most colourful, are found on and around coral and rock reefs. The plant feeders include Rabbitfishes, which are very common in shoals along the shallow reefs and are a well-used source of market fish. The Stellate rabbitfish (Siganus stellatus), Forktail rabbitfish (S. argenteus), Rivulated rabbitfish (S. rivulatus) and Coral rabbitfish (S. corallinus) all occur around Cousine. The fin spines of rabbitfishes are poisonous, and these fishes should be handled with great care. In life, an undisturbed Forktail rabbitfish is silvery with small white spots and yellow on the head and back. A speared fish immediately develops large white spots. On being taken off the hook and placed into water it develops a pattern of brown bars and marbling finally becoming brown with blue spots after death. A conspicuous group of fish, which are mainly herbivores, are the surgeonfishes, named from the scalpel-like spine which folds into a groove in the tail. The spines are used offensively or defensively, in struggles for dominance or against predators, and can leave deep wounds. Included in the reef and rock species around Cousine are the common yellow and black barred Convict surgeonfish (Acanthurus triostegus), the yellow and blue Striped surgeonfish (A. lineatus), the Powder-blue surgeonfish (A. leucosternon) and the Yellowfin surgeonfish (A. xanthopterus). Desjardins sailfin tang (Zebrasoma desjardinii) with its zebra-like dark brown and white bars and large rounded fins is as striking as the unicornfishes, which have a horn protruding from the head of some species, and include the Spotted unicornfish (Naso brevirostris)
. A unicornfish without a horn is the Orangespine unicornfish (Naso lituratus). All the young unicornfishes feed on benthic algae and on zooplankton as they get older.
A Powder-blue surgeonfish, patrolling a head of staghorn coral. The Moorish idol (Zanclus cornutus) is a striking fish with a contrasting yellow, black and white pattern, a long, pointed dorsal fin, a pouty mouth and a puffed out chest. It feeds on sponges and occurs from shallow, turbid water to clear seaward reefs as deep as 180 m. Other sponge eaters are Angelfishes which also feed on algae and encrusting invertebrates. These are popular aquarium fishes. The juveniles bear beautiful circular and semicircular patterns of black and blue and white, and the adults are no less colourful in their variety of colours and patterns. The Emperor angelfish (Pomacanthus imperator), Sulphur damsel (Pomocentrus sulphureus) and Caerulean damsel (P. caeruleus) may all be seen in the reefs and rocks.
Moorsish idol cruising over coral rubble.
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A Three-spot angelfish, foraging for sponges.
Semicircle angelfish with a Moorish idol in the background.
Butterflyfishes are small and delightful inhabitants of the reef: Racoon butterflyfish, favours the turbulent water where it feeds on a variety of plants and small animals (top left); the Blackback butterflyfish eats corals (middle); the Yellowhead butterflyfish, feeds on a variety of corals and other invertebrates (bottom right); a pair of Redfin butterflyfish, patrol the reef feeding specifically on coral and holding territories (bottom right).
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Of great importance to the formation of sand in coral reef areas are the parrotfishes, so-called because many have a horny curved beak resembling the beak of a parrot, and many are brightly coloured. Except for some of the larger species, they are herbivorous, scraping benthic algae from dead coral and algal films growing on compacted sand substrate or on sea grasses. Typically, the toothmarks left after larger parrotfish have been feeding resemble the marks left by rodents gnawing on hard objects. The rock fragments and coarse sand particles are ground up to fine sediment, the algal food is digested and the sediment is passed out. In doing so, they contribute to the formation of coral sand in tropical seas. Some species have interesting night-time behaviour, when they find a crevice, secrete a protective cocoon and go to sleep. The giant of the parrotfish is the Bumphead parrotfish (Bolbometopon muricatum), growing to well over a meter long and weighing over 46 kg. A virtually uniform dark green when adult, the species is one of the few parrotfish which feeds on living coral, and the crunching sound of its feeding can be heard for some distance underwater. It is a highly threatened species, which was also suffered a local population decline as a result of the great bleaching event.
A bullhead parrotfish cruising and grazing on coral.
Closely related and often confused with parrotfish are the equally colourful wrasses, which have small to moderate mouths and conical teeth, usually with some canines anteriorly. Although most wrasses prey on a variety of invertebrates, including hard-shelled molluscs, sea urchins and crustaceans, which they crush with their teeth, some such as the Tripletail wrasse (Cheilinus trilobatus), prey heavily on fishes. The Cleaner wrasses feed on ectoparasites of other fishes (see p ). Among them is the Bluestreak cleaner wrasse (Labroides dimidiatus), and the Bicolor cleaner wrasse (L. bicolor). Cleaner wrasses are territorial around prominent coral formation known as cleaning stations. The cleaner wrasses advertise these stations by 'dancing', swimming with a distinctive up-and-down motion. Fish go to these stations to have their ectoparasites or diseased or damaged tissue removed. Some will solicit cleaning by lying with their fins and gill covers flared or will literally wait in line for their turn. Cleaner wrasses can even safely enter the mouths of large predatory fish in exchange for services rendered. Showing marked sexual colour differences is the Candycane longface wrasse (Hologymnosus doliatus), often caught by fishing over reefs using fish bait. The Indian Ocean bird wrasse (Gomphosus coeruleus) has a long pointed beak-like snout, which it uses to probe corals for small crustaceans, molluscs, fish and brittle stars. The Yellowtail wrasse (Anampses meleagrides) is an inhabitant of mixed coral, rubble and sandstone platform. It is a beautiful fish showing strong sexual dimorphism. The females are dark brown with a white spot on each scale, white spots on the head and fins, and a tail of bright yellow. The male is orange-brown with blue spots, the tail having a white crescent, edged with blue. Other feeders on hard foods such as sea-urchins, calcareous algae, coralline seaweed and coral polyps are the Triggerfish. They have sideways compressed bodies with strong, rough scales, a strong first dorsal spine (often sharp and barbed), which can be raised and locked in position with the second dorsal spine. The spine is used to wedge the fish into crevices, from whence they are extremely difficult to dislodge by predators. They have strong incisor teeth, which are used to crush prey or snip off pieces of coral, and, on occasion, pieces of careless diving humans who are bitten by male Triggerfishes guarding eggs.
Starry triggerfish (Abalistes stellatus), Bridled triggerfish (Sufflamen fraenatus), Black triggerfish (Melichthys niger), and Wedge picassofish (Rhinecanthus rectangulus) are all found around Cousine. A fish with projecting spines which are not retractable, but are fixed as part of the animal's skeleton, is the Thornback cowfish (Lactoria fornasini). It has a hard squarish body covered with a shell of bony plates. It has five spines, two on the forehead, one on the back and two pointing backwards on the underside. The fish has small soft fins and is a slow-moving diurnal feeder on small sessile invertebrates and algae. Of somewhat similar body shape and also with relatively weak soft fins are the puffers, which do not have a hard bony shell. They are able to inflate their soft bodies by drawing in water into a specialized chamber near the stomach. The resulting sudden size change is often enough to persuade a would-be predator to skip lunch. Goatfishes have a prominent pair of long barbels under the chin, and a small mouth with a slightly protruding upper jaw. The barbels contain chemosensory organs and are used to probe the sand or holes in the reef for the benthic organisms or small fishes on which the goatfishes feed. Goatfishes are highly esteemed as a food both by humans and by some fish. The Yellowstripe goatfish (Mulloidichthys flavolineatus) is common on the reef, while the Yellowsaddle goatfish (Parupeneus cyclostomus) occurs in the granite subtidal areas. Soldierfish and squirrelfish and Cardinals shelter in caves and crevices or among branched coral during the day, and emerge at night to feed. Both groups have large eyes and mouths. Soldierfishes and squirrelfishes are predominantly red in colour, with many being striped red, black and white. During the night, soldierfishes forage above the reef feeding mostly on crustacean larvae, while squirrelfishes forage close to the bottom for crustaceans, worms and small fishes. The Long-jawed squirrelfish (Sargocentron spiniferum), the largest (to 45 cm) in the group, is red in colour with a long, poisonous spine on the operculum. It feeds at night on small crustaceans, worms and fish.
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Smaller-sized species include two endemics, the Seychelles soldierfish (Myripristis seychellensis) and the Seychelles squirrelfish (Sargocentron seychellense), while a number of other species occur around the Island.
Fishes eating a variety of invertebrates and small fish include the sweetlips, emperors, snappers, and groupers. The common name of sweetlips is derived from their thickened lips. They generally shelter under corals or overhangs during the day and forage at night. Some species are colourful and undergo dramatic changes in their colour as they grow larger, including the Oriental sweetlips (Plectorhincus orientalis). Juveniles under 150 mm are dark brown with large cream blotches, while adults are striped black and white and have yellow and black fins.
Seychelles soldierfish (above) and Seychelles squirrelfish (below).
The Oriental sweetlips is regularly seen hugging the coral walls around Cousine. A cleaner wrasse can be seen just in front of the pectoral fin, searching the host's body for parasites.
To lighten Squirrelfishes, soldierfishes and a Moorish idol sheltering among the coral overhangs. The cardinalfishes also include a number of red species, but some drab and many striped species as well. They typically disperse at night to feed on zooplankton and small benthic crustaceans. The male broods the eggs in his mouth until they hatch, after which the young disperse to care for themselves. While a number of species have been seen around Cousine, only two have been identified: the Blackbanded cardinalfish (Apogon cookii) and the lined cardinalfish (Cheilodipterus artus).
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The emperors are well represented around Cousine. These fish have thick lips, canine teeth in front of the jaws and feed mostly on hard-shelled invertebrates (crustaceans, molluscs, sea-urchins) at night. Most of the emperors have silvery bodies with some yellow, red or orange on the body and fins. An exception is the Blue-lined large-eye bream (Gymnocranius grandoculis) which has blue lines on the snout and the strikingly marked Spangled emperor (Lethrinus nebulosus), with patterning of blue and yellow on the body, and yellow fins. A number of yellow, orange and red marked emperors are frequently caught by creole hand-line fishermen, including the Variegated emperor (Lethrinus variegatus) and the Sky emperor (L. mahsena).
The snappers are robust fish with large canine teeth in both jaws, feeding mostly on crustaceans, but also on small fishes. They are among the most important commercial fishes in tropical and subtropical regions, and include some fine game fish such as the Green jobfish (Aprion virescens). These are voracious hunters occurring singly or in small groups above outer reef slopes. A bright red snapper with white edging to the hind fins and pectorals is the Humpback snapper (Lutjanus gibbus). During the day, adults may occur in large aggregations along the upper edge of reef slopes. Beside their main diet of crustaceans, they also feed on echinoids, worms, octopuses and small fishes. The common yellow and orange Black-spot snapper (Lutjanus fulviflammus) occurs in small shoals among reefs and rocks. The Twinspot snapper (Lutjanus bohar), which is a dark grey to blackish-red fish, with two prominent white spots on its back, feeds primarily on fishes. It is the frequently poisonous and is banned from sale in many areas. Ciguatoxins lead to ciguateria poisoning in humans resulting from eating fish which have become poisonous by feeding on certain toxic microorganisms, or which have eaten prey which have fed on such organisms. Although such poisoning is common in the Pacific, it is rare in the Seychelles. The groupers or rock cods are large-mouthed strong fish, living on the bottom, and often sheltering in overhands, caves or crevices. There are some showy animals among these normally brown and black fishes, such as the Coral hind (Cephalopholis miniata) which is bright red with evenly spaced round blue spots, while the Peacock grouper (C. argus) is brown, sometimes with lighter bars, and is spotted with blue spots. The anterior part of the dorsal fin is tipped with red, and the caudal half of the pectoral fin is an unspotted deep wine red. All the groupers are carnivores, eating crustaceans and small fishes and some are potentially able to reach large sizes. One Seychelles species, the Potato grouper (Epinephelis tukula) may reach 110 kg and feeds on fish, sometimes on crabs and octopuses. Smaller species of the brown and speckled rock cods include the Foursaddle grouper (E. spilotoceps) and the Whitespotted grouper (E. caeruleopunctata).
Two fish which are flattened from side to side and rounded in shape, generally silvery in colour and living above reefs are the Mono (Monodactylus argenteus) and the Longfin spadefish (Platax teira). Both are carnivores, and feed on crustacea and worms. The Mono is associated with estuaries, but also ventures over silty reefs, and can also live in freshwater. Spadefish juveniles have elongated fins and live in sheltered lagoons, while the adults occur in small groups of up to ten on the seaward side of reefs. Two fish which are flattened from side to side and rounded in shape, generally silvery in colour and living above reefs are the Mono (Monodactylus argenteus) and the Longfin spadefish (Platax teira). Both are carnivores, and feed on crustacea and worms. The Mono is associated with estuaries, but also ventures over silty reefs, and can also live in freshwater. Spadefish juveniles have elongated fins and live in sheltered lagoons, while the adults occur in small groups of up to ten on the seaward side of reefs. Reputedly the most poisonous fish in the sea is the squat, drab-brown Stonefish (Synanceia verrucosa). The dorsal fin has 13 hollow spines each with a poison sac at their bases. The eyes are small and deeply set in the head and the mouth is wide and points upward. The stonefish adopts a hunting strategy of lie-andwait for its fish prey. In so doing it is very well camouflaged, looking like a seaweed-encrusted rock. Because it occurs on shallow reefs, rocks and sometimes sand, the stonefish can easily be walked on. The treatment for the very painful and often lethal poison is, as with rabbitfish and ray spine injuries, soaking in very hot water for at least 30 minutes to denature the proteins in the poison.
The highly camouflaged stonefish has very poisonous spines.
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Fishes of the inter-tidal zone Intertidal rock pools are used by small fish, while on the rubble flats some species of blennies, gobies and eels are able to survive low tides as long as there is some water, or even wet sand, as shelter against sun and wind. The Maned rockskipper (Damania anjouana) is commonly seen resting on rocks out of water. When disturbed it leaps and skips down the rock, and across water, to escape. It has a handsome dark, barred body and greatly elongated dorsal fin rays. Other rockskippers are Dussumier's rockskipper (Istiblennius dussumieri), Picture rockskipper (I. gibbifrons), Rippled rockskipper (I. edentulus) and Blackspotted rockskipper (Entomacrodus striatus). The small Hourglass triplefin (Enneapterygius elegans) is fairly common in the granite rockpool areas. Barred flagtail (Kuhlia mugil), Fringelip mullet (Crenimugil crenilabrus) and the ubiquitous sergeants Abudefduf spp. and damselfishes (Plectroglyphidodon spp. and Chrysiptera spp.) are found in virtually all larger pools.
When the incoming tide pushes over the rubble flats, many reef fish come in to feed. These include colourful species such as the Oriental sweetlips (Plectorhinchus orientalis), Tripletail wrasse (Cheilinus trilobatus), Goldbar wrasse (Thalassoma hebraicum), Redlip parrotfish (Scarus rubroviolaceus), Stareye parrotfish (Calotomus carolinus), rabbitfishes (Siganus spp.), Yellowfin surgeonfish (Acanthurus xanthopterus) and Dusky sweetlips (Plectorhinchus chubbi). In the intertidal area on sandy beaches or in areas where sand patches form the matrix for rock outcrops, coral heads or rubble piles, the fish fauna remains much the same as that in the sub-tidal areas. Of note are the Blackspot emperor (Lethrinus harak) and the Small-spotted pompano (Trachinotus bailloni). The latter forages extensively in the swash zone and on close, inshore sandy areas.
Small-spotted pompano.
Implication of the great coral bleaching event for the fish
Maned rockskipper, although a fish, spends much of its time out of the water when the tide is out. Small wrasses, such as juvenile Surge wrasse (Thalassoma purpureum) and Dusky wrasse (Halichoeres marginatus) are occasionally seen. At night, the Convict surgeon (Acanthurus triostegus) visits pools which they do not normally frequent during the day.
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The great coral bleaching event of 1998 in the Seychelles (Graham et al. 2006) clearly had a major effect on the corallivorous (Samways 2003), as well as the planktivorous (Graham et al. 2007) fish. While there has been no detectable effect on fisheries yield, the concern is the change in size structure of the fish communities, with a decline in smaller fish (45 cm). This probably represents a time-lag response to a reduction in reef structure and complexity brought about because fishes are being lost through natural mortality and fishing, and are not being replaced by juveniles. This, in turn, will inevitably affect fisheries productivity in the longer term (Graham et al. 2007). As the impact appears to be similar outside Marine Protected Areas as inside, the outcome for Cousine will be similar to elsewhere in the granitic Seychelles.
COUSINE AS A HAVEN FOR TURTLES Firstly, a note on amphibians Before embarking on a discussion of turtles - those highly threatened and charismatic reptiles which need so much protection and are very significant to Cousine - we should first mention the amphibians. Caecilians are specialized amphibians, burrowing, limbless amphibians confined to the tropical region of the world. Seven endemic species occur in the Seychelles. They live in moist litter and soil or rotten logs. Some enter streams, and feed on a wide variety of invertebrates. Although no caecilians are known from Cousine, Cousin Island is reported to have caecilians. It also has a permanent swampy area, lacking on Cousine, which may be the reason for this. Five species of frogs are known from the Seychelles. Of these, four are endemic. No frog or toad is known from Cousine, probably because of the historical lack of permanent natural water bodies, and occasional dry spells. Except for the Yellow-bellied sea snake (Pelamis platurus), there are no poisonous or otherwise dangerous reptiles in the Seychelles (Bourquin and Hitchins 1998). The large (over 6 m) saltwater crocodile (Crocodylus porosus) used to occur in the Seychelles, but became extinct by the mid 1800s.
Exploitation of turtles Mostly between August and March, animals of great significance land on Cousine to nest. These are two species of sea turtles, both considered in dire need of protection worldwide, and both still being used illegally for food and as a source of other products. Although some legislation has been in effect, law enforcement is rarely pursued, and particularly the more favoured Green turtle (Chelonia mydas) has suffered drastic population declines. Turtles have probably always been under pressure by humans, but especially so since ships began to ply the seas. The value of turtles to early seafarers is emphasized by an entry in a Survivors' Manual kept aboard lifeboats, where turtles, which often have a natural curiosity for small boats, were described as easy to catch and make an excellent meal. Their flesh was said to be tasty, and their blood salt free and nutritious. Their eggs, in turn, were described as a real treat.
Not only does the green turtle, and the second breeding species, the Hawksbill turtle (Eretmochelys imbricata) suffer direct exploitation by humans, but the beaches on which they nest are subject to more and more disturbance and development, and available breeding grounds are declining. Hatching turtles can become disoriented by any artificial lights on or behind beaches and may because of this, never reach the sea. From the turtle tracks, it is possible to determine whether a turtle has nested or not.
Up tracks of the Hawksbill turtle: the ovipositor being firm, the tip of the tail touches the sand intermittently
Down tracks: The ovipositor being relaxed from egg laying, the tip of the tail drags continuously on the sand
Turtle breeding on Cousine's shores Male sea turtles rarely come ashore again after their initial brief, hazardous sojourn to the sea as hatchlings, and even mating takes place in the sea. The only record of a male emerging onto the beach in the Seychelles was on Cousine in November 2003. Details of nesting of the Hawksbill turtle have given by Hitchins et al. (2003a,b, 2004a,b, 2006) and genetics by Okayama et al. (1999), and some notes on the nesting of the Green turtle on Cousine are given by Lawrence (2007a).
Tropical Island Recovery: Cousine Island, Seychelles.1st edition. By Michael Samways, Peter Hitchins, Orty Bourquin, and Jock Henwood. Published 2010 by Blackwell Publishing Ltd.
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A very rare case of a male Hawksbill turtle basking on the beach with the waves gently lapping around its body. The extended tail is characteristic of males. By far the rarest turtle to nest on Cousine is the Green turtle, with only 25 nests having been recorded in recent years, in most months with the exception of March, April, May and October. It is the larger of the two species, having a carapace (upper shell) length of up to 1.2 m, and usually weighing up to 210 kg. Exceptionally, weights in excess of 270 kg, are attained. Adult Green turtles, despite their name, vary in colour and patterning (as with all species, no individual is ever exactly the same), the shell varying from pale red brown to dark brown, with blotching and streaking of pale brown, yellow, gold and red brown. The underside ranges from pure white to pale yellow. Hatchlings are a dark olive to black with white edging to the flippers and shell. They are 45 mm to 52 mm long on hatching, and weigh between 18 and 30 g.
A rare sight: Green turtles mating in the waves off the Cousine Island beach.
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Green turtle digging nest hole.
Camouflaging her nest.
By the time the nesting process is fully completed, the Green turtle is totally covered/camouflaged with beach sand, most of which falls off on the journey back to the sea.
A Green turtle returning to sea having lost most of the beach sand on its head and carapace.
Green turtle hatchling, with its characteristic white-edged flippers. Comparing adult tracks; Green turtle (left) and Hawksbill turtle (right). Adult Hawksbill turtle colouration is variable, usually being dark brown with faint yellow streaks and blotches, with the ventral surface being pale yellow. The Hawksbill turtle reaches carapace lengths of up to 96 cm and weighs from 48 to 93 kg on Cousine island.
Hawksbill turtle hatchling.
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Turtles emerge very cautiously from the sea, frequently peering around with their heads held high before crawling to a suitable nest site. The beak of the aptly named Hawksbill turtle. Hatchling colouration varies in shades of brown on both the carapace and plastron. Sometimes they have black edging to some of the scutes. The flippers are dark brown with paler edges which is not as marked as in Green turtle hatchlings. Hawksbill turtle hatchlings are between 33.5 mm and 43.5 mm long, and weigh 9.6 g to 21.1 g. Nesting behaviour of the Green and Hawksbill turtles follows the same basic procedure as in all marine turtles, and can take from an hour to over three hours to complete. The Green turtle is a night nester, whereas uniquely in the Seychelles, the Hawksbill turtle nests mainly during daylight hours. Turtles emerge very cautiously from the sea, frequently peering around with their heads held high while crawling up the beach in search of a nest site. Hawksbill turtles while advancing up the beach sometimes pause and push their snouts towards the sand as though smelling for direction. On what basis nest sites are selected is not clear, but prior to actual egg laying, a female might make several exploratory sweeps with her fore-flippers and then starts to scrape out a body pit with her front flippers. The nest hole is then dug with the hind flippers. Sometimes this procedure will be repeated several times before the female finds the right site. The preferred site is where the sand walls of the hole being dug do not collapse. The nest hole is carefully dug, and at the bottom an egg chamber is hollowed out.
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Egg laying is done with eggs leaving the ovipositor in ones, twos or threes, coated with a mucous, which also drips into the nest between eggs. After egg-laying has started, the turtle can be measured, examined, tagged and photographed without her leaving her nest, prior to egg laying she will generally abort her attempt at nesting if disturbed.
Adult Hawksbill turtle laying eggs. The hind part of the body is lowered into the nest hole. The eyes are also closed as the eggs leave the ovipositor. Once the eggs are laid, her dexterous hind legs are used to put sand into the nest hole and tamp it down firmly. Then she covers the body pit with vigorous backward sweeps of her fore flippers and scrapes the sand with her hind flippers. She then moves away from the nest while continuing to fling the sand backwards and churning with her fore flippers until the nest hole is well camouflaged. The nestcamouflaged areas can vary considerably in length from 1 to 12 m. Satisfied with the procedure, the turtle then makes her way back to the sea until her next nesting.
Predation by ghost crabs of both eggs and hatchlings can be very high. Although this is a natural process, it is a conservation management practice on Cousine to move nests within 12 hours from areas of high crab densities to those of low densities, to improve the hatchlings' chances of survival. Furthermore, nests that stand a chance of being damaged or flooded by the sea are also moved to safer localities. This has become necessary as turtles have become globally threatened and the number of hatchlings returning to the sea must be maximized to lend support to their population growth. The powerful front flippers can fling sand backwards for up to 6 m.
Hawksbill turtles lay an average clutch size of 171 eggs, with a maximum of 264 having been recorded.
Returning to sea with head held close to the ground.
While the turtle is in the process of laying eggs, biting flies (tabanids) have the opportunity of settling on the immobile turtle's soft body parts that cause her great discomfort as they bite her.
At intervals the turtle stops with the head held high in surveillance of its surroundings.
Camouflaging the nest hole site. The peg at the left top of the picture is the site of the egg chamber.
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Now about to slide down a high vertical bank carved by the sea.
At last the sea.
Each turtle may nest up to five times in a season at 12 to 18 day intervals and will often return to the same place on the same beach to do so. Turtles may also use two islands on which to nest during a season, and turtles tagged on Cousin and Aride have been found beaching and nesting at Cousine, and vice versa. Occasional Cousine individuals have also nested on Mahé. Due to the proximity of Cousine and Cousin to each other there is a high interchange of breeding females. Individual turtles do not nest on the same beaches in successive years. On Cousine, the intervals between nesting seasons for individual Hawksbill turtles have ranged from two to four years, with half of these coming out in two-year intervals, 42% in three-year intervals, and the rest in four-year intervals. Turtles which nest on Cousine's beach will occasionally use beaches on other islands for nesting, so we cannot be sure that an individual that has been seen at a four-year interval has not nested elsewhere during that time. Most of the long term tagging programmes have resulted in the realization that many breeding females are recorded only once for an area. This means that they are possibly being killed or they may be shifting their breeding areas. The time between egg-laying and hatchling emergence from the nest is mostly 54 to 70 days, depending on substrate, and hatchlings may spend two or more days in the nest before emerging.
A Hawksbill turtle at home in the ocean just off the Cousine reef. The number of eggs per clutch range from 12 to 276 (mean = 165) for the Hawksbill turtles, and is similar to that of the Green turtles.
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Hatchlings emerging from the nest chamber below.
The hatchlings start heading for the sea.
Hatchlings heading en masse for the sea.
Finally the freshness, and the danger, of the sea… The incidence of albinism in turtles in the Seychelles is very rare (Hitchins and Bourquin 2006). On Cousine, some 74 020 Hawksbill turtle hatchlings were examined between 1995 and 2004. Of these, two from one nest in 1999 displayed partial albinism of the fore-flippers, yet had no other apparent morphological deformities and were
A rare example of Hawsbill turtle hatchlings with albino flippers. One major difference between Green and Hawksbill turtles in the granitic Seychelles is that Hawksbill turtles normally come out to nest during daylight hours, while Green turtles generally nest during the night. The hatchlings of both species generally emerge from the nest at night (dusk to dawn). The Hawksbill turtle feeds on various organisms such as sponges, tunicates, molluscs and algae on coral reefs, while the Green turtle is mainly herbivorous. Cousine's sister island, Cousin, has always been an extremely important breeding area for Hawksbill turtles, with at least 90 females breeding there each year. Cousine is now also playing a major role in sea turtle conservation. During the 1995/96 breeding season 21 individuals were recorded beaching or nesting on Cousine, with this number increasing to 68 females being recorded, 54 of which nested again four years later. Cousine's contribution to the conservation of turtles has been enormous, with increasing numbers nesting on Cousine each year. There were, on average, 30 nests per year from 1992 to 1995, increasing to 68 nests per year from 1995 to 2000, to 83 nests per year from 2000 to 2006. The larger but more populous islands of La Digue, Praslin and Mahé together host an estimated 55 breeding females. Although the presence of extensive beaches should be home to far more breeding turtles, there is a great deal of disturbance and considerable poaching, which has greatly reduced turtle breeding activities.
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A mere 300 breeding females is believed to occur in the granitic Seychelles, of which almost half breed on Cousin and Cousine Islands. It is considered that Cousine ranks in the top three islands of importance to nesting Hawksbill turtles in the granitic Seychelles. Althought the giant Leatherback turtle (Dermochelys coriacea) and the Loggerhead turtle (Caretta caretta) have been recorded from the Seychelles, there are no breeding records, and neither has been seen near Cousine.
This unusual picture shows the interaction between three threatened species. The Hawksbill turtle is digging a nest, and by doing so, has attracted the attention of both a Seychelles magpie robin and a Wright's skink, both seizing the opportunity to pick up disturbed prey items.
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OF TORTOISES, LIZARDS AND SNAKES Cousine as a refuge for giant tortoises Tortoises, like turtles, were once widespread on several islands in the western Indian Ocean. They were a readily accessible source of fresh meat for early seafarers between long stretches of ocean and where mammalian food was scarce. They were harvested in their thousands and taken aboard ships where they were kept alive, even without food, for weeks and slaughtered as needed. They were even kept upside down to prevent their wandering. A conspicuous inhabitant of the Cousine plain, especially in the well-wooded area around the base of the granite, is the Aldabran giant tortoise (Aldabrachelys gigantea). Twenty one individuals were introduced from 1992 to 2004, which came mainly from Aldabran stock, where an endemic, surviving population still exists. There has been much debate over the years as to whether there were perhaps three species of giant tortoise on different islands in the Seychelles island group ('Dipsochelys arnoldi', 'D. hololissa' and 'D. dussumieri'). An extensive genetic study has now resolved this issue, with all three now considered to be forms of the species gigantea within the genus Aldabrachelys (Fritz and Bininda-Emonds 2007). The Cousine tortoises are of mixed origin, but all were from captive stock on mainly Mahé and Praslin. Out of the 21 introduced individuals, 20 subsequently survived and are thriving.
Two of the tortoises on Cousine have the heavier and more sculptured appearance of the original form from the granitic Seychelles giant tortoises (see Bourquin and Hitchins 1998, Gerlach and Canning 1998, Polkovacs et al. 2002, Gerlach 2003a, Gerlach 2004b, Karanth et al. 2005 for more details). This form was virtually destroyed by humans in the granitic Seychelles, and was thought to have become extinct before the end of the 18th century. However, after a detailed survey of captive tortoises throughout the Seychelles, it was found, to the delight of conservationists, that individuals of the granitic Seychelles form still existed. In response, a breeding programme was started on Silhouette Island, in an urgent attempt to resurrect viable breeding populations of this and another form, Arnold's giant tortoise. The population of Arnold's giant tortoise, has now increased to over 40 individuals, but the situation with the Seychelles giant tortoise is still precarious.
A rare example of a male giant tortoise wandering on the beach.
This individual is probably of mixed genetic ancestry with a morphology between that of the original tortoises from the grantic Seychelles and those from Aldabra.
The largest tortoise on Cousine, a male known as Albert, had a carapace length of 1.53 m and weighed 287 kg in January 2002. The weights of the ten males on Cousine range from 184 to 287 kg, with an average weight of 233 kg. The nine females have an average weight of 108 kg with a weight range of 40 to 125 kg. The heaviest known tortoise in the Seychelles weighed 304 kg, and was an animal introduced to Bird Island.
Tropical Island Recovery: Cousine Island, Seychelles.1st edition. By Michael Samways, Peter Hitchins, Orty Bourquin, and Jock Henwood. Published 2010 by Blackwell Publishing Ltd.
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Giant tortoises eat a wide variety of plants, including sedges, grasses, broadleaf herbs, fallen tree leaves and fruits. Feeding is mainly in the early morning and late afternoon, although on cool days, feeding can take place throughout the day. Their food is not chewed, but is simply bitten off and swallowed. The seeds of many fruits pass through the tortoises unharmed and are thus distributed when purged. When giant tortoises were numerous in the granitic Seychelles, they probably played an important role in ecological processes by dispersing large numbers of seeds. On Aldabra, 28 species of plants and shrubs were germinated from seeds collected from giant tortoise faeces.
SEEDS FOUND IN TORTOISE FAECES ON COUSINE
Ochrosia.
Nibbled flesh of Indian almond.
Tortoises consume many types of seeds which subsequently pass through their digestive tract and ready to germinate away from the mother plant. Morinda.
Whole seeds of Indian almond.
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Aldabra Island is a harsh environment, due primarily to the low rainfall. The limited available water accumulates in small, shallow pools, and the tortoises have developed the ability to drink water through their nostrils.
A tortoise at night submerged in a pool in the drainage line forest to partially escape the ravages of mosquitoes.
The nostrils of the Seychelles giant tortoise are adapted for drinking water from shallow pools. Specially constructed concrete bathing pools are used by the giant tortoises on Cousine. The tortoises often lie in the water, their long necks stretched out on the bottom of the pool, eyes closed and to all intents and purposes looking as though they were fast asleep. This behaviour may well be to escape the hordes of mosquitoes which feed on tortoise blood.
The algal growth on this tortoise's head is testament to the large amount of time that it has had its head under the water for relief from persistent biting by mosquitoes.
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During the hot hours of the day, tortoises sleep in shaded areas, usually with their legs, head and neck outstretched on the ground. At night they sleep in a more relaxed pose with the eyes always closed. Such behaviour is an indication that they have evolved in the absence of large predators. It also assists in dissipation of heat from its body.
Giant tortoises mating.
A giant tortoise at rest during the day, with its head extended.
A giant tortoise sleeping at night. The breeding season of giant tortoises in the Seychelles occurs between December and August, with a peak in April. On Cousine, copulation has also been recorded during October and November. Successful copulation is known to be very rare, and only with about 2% success on Aldabra. During copulation, the males are very noisy, making a variety of grunting and groaning sounds. Nesting begins in May or June. Nesting sites must have a sufficient soil depth (about 50 cm) and about six hours of direct sunshine per day.
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The nest is dug during early morning, late evening and at night by the female using her hind feet to do so. Before the nest hole is complete, she releases large quantities of mucous-laden urine, filling the hole and saturating the nearby area. Having laid her 4-28 billiard ball-size eggs, she spends three to six hours filling the nest cavity. The entire nesting process takes at least 11 hours. Within 36 hours, the surrounding earth will have dried, encasing the nest in a concretelike layer which protects the eggs. Incubation varies from 73 to 160 days. The earlier in the season that the nests are laid, the longer the incubation period. Hatching takes place just before the rainy season, with hatchlings staying in their nests for one to two weeks before emerging. The survival rates of giant tortoises up to five years old, range from under 5% to 31%. Better survival occurs when tortoise densities and egg predation are low. On Cousine, egg laying has been a rare occurrence, with only six nests recorded between 1996 and 2007. This poor record is possibly due to the females just reaching sexual maturity combined with the too shallow soils on the plain. The unsuccessful nests contained between eight and 28 eggs, each weighing between 49.8 and 65.8 g.
Giant tortoise nest accidentally exposed during excavation in the deeper soil at the base of a granite outcrop.
Giant tortoise dung contains many seeds. The plastic- bag that was eaten fortunately passed through the tortoise. Litter is one of the dangers facing these animals.
Stripeless day gecko.
Mating pair of Stripeless day geckos.
Geckos Stripeless day gecko The Stripeless day gecko (Phelsuma astriata) has been recorded from St Joseph, D'Arros, Denis, Praslin, Curieuse, Round, La Digue, Felicité, Petit Soeur, Grand Soeur, Marianne, Cousin and Aride and is endemic to the granitic Seychelles (Losos 1986).
This species is widespread on Cousine. The largest individual recorded on the Island had a snout-vent length (the length from the tip of the snout to the cloaca) of 52 mm, close to the largest (53.3 mm) recorded for the species. As with all geckos, the tail is easily broken off, wriggling to take a would-be predator's attention off its escaping prey. The species is either a plain grass green, or green with pink to red markings on the head and back. Breeding is year round, and two, joined eggs are laid in a crevice, each egg measuring about 10 mm x 8 mm. The species is arboreal, using a variety of trees, and freely enters buildings. It is diurnal, eating mainly small insects, although it also forages around lights at night.
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Bronze gecko A large (up to 110 mm snout-vent length, and up to 220 mm total length) species, the Bronze gecko (Ailuronyx seychellensis) is endemic to the granitic Seychelles and has been recorded from Mahé, Saint Anne, Conception, Therése, Frégate, Praslin, La Digue, Felicité, Cousin and Aride. It breeds all year round, and its single or joineddouble egg clutch is laid in crevices on tree trunks, on the undersides of sheltered woody coconut spathes, or in the corners of walls in buildings. The eggs are cemented to the substrate and each egg is about 17 mm long by 16 mm wide.
Adult Bronze gecko.
Adult Bronze gecko sunning itself on trunk of a tree, and camouflaged, having turned dark brown. The Bronze gecko is nocturnal, and is found in buildings and on boulders, tree trunks, branches and leaves of trees, although it is also seen foraging on ground at night. It will feed readily on insects attracted to lights in houses, stalking these with such a slow creep that its movement is barely perceptible. It occasionally also feeds on fruit.
A young Bronze gecko showing the characteristic light lines, bordered by dark brown, along the body. The skin of this gecko tears easily, and following mating (where the male grabs the female rather violently in its jaws) a gecko may be seen displaying bald pink patches. The skin grows back again and the animal does not appear to suffer any permanent damage. Single and double eggs of the Bronze gecko laid behind a picture on the walls of a building. The scars of previous eggs can also be seen.
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Pacific gecko
Bronze gecko removing and eating its own sloughed skin. When exposed on pale surfaces, the species' markings fade. On dark surfaces, attractive patterns of black and dark brown on grey or light to dark brown become evident. The lizard's body can display a pattern of dark broken lines, and the limbs, tail and head usually have dark reticulations. Young animals have a characteristic light line running along each side of the head, although this marking is often absent in adults.
The Pacific gecko (Geyhra mutilata) has a snout-vent length of 58 mm, and occurs on Mahé, Saint Anne, Cerf, Silhouette, North, Bird, Frégate, Denis, Praslin, Curieuse, La Digue, Grand Soeur, Coetivy, and Cousine. It was introduced by humans and does not occur on unoccupied islands. It was first recorded from Mauritius during the early 1800s, probably introduced from East Asian islands. It was probably brought from Mauritius to the Seychelles where it was first recorded in the 1860s. This gecko is a nocturnal species found occasionally in buildings, catching insects around lights. Its colour is a very pale grey to pink-grey at night under lights, but when not exposed to bright light while on a pale surface, the colour is grey, indistinctly speckled and marbled with a darker grey. The tail is somewhat flattened and appears to have articulations, especially near the base. This lizard readily sheds its tail, skin and even its digits when it is caught or handled.
A pair of geckos.
Seychelles sucker-tailed gecko
The foot of a Bronze gecko showing the unique scales (scansors) that allow them to stick to smooth surfaces. Note also the small curved claws.
The Sucker-tailed gecko (Urocotyledon inexpectata) is endemic to the Seychelles and has been found elsewhere on Mahé, Silhouette, Frégate, Praslin, Curieuse, La Digue, Felicité, Grand Soeur, Cousin and Aride. It is nocturnal, and rarely encountered, with a few records from coconut palm trunks and rock crevices.
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Their pink, grey and brown patterning camouflages them well. Their snout-vent length may reach 40 mm, with a total length of 80 mm. A curious feature of this little animal is a small pad on the underside of the end of its tail, possibly used to help the gecko cling to its substrate. The toes are distinctly tipped on the underside with a pair of pads for adhesion.
Seychelles skink The Seychelles skink (Mabuya seychellensis) is endemic to the central Seychelles and Amirantes, and is common on Cousine, from the upper beach to the hill top, and from coastal plain to granite coastal areas. As with the Bronze gecko, the species is most common on sea-bird breeding islands. It forages on the ground, on trees and rocks and in and around houses, from open areas to closed forest and on coastal boulders. The number of individuals on Cousine is estimated at about 16 800, with a total biomass of 452 kg (Ball 2001). It is generally brown to dark brown above, with a dark brown to black line running down each side of the body. The dark line is flanked by two whitish or pale yellow lines, and the back is speckled with small white dots. The chin is white, and the belly bright orange-yellow.
The Seychelles skink is also arboreal and will push seabird eggs from unattended nests to the ground and eat the contents. This species can reach 108 mm snout-vent length and total lengths of about 220 mm, weighing up to 39 g. It lays three to seven elongated eggs measuring about 19 x 13 mm in soil or under rocks and logs. Hatchlings are about 98 mm in total length, and weigh about 1 g. Both these and older juveniles are readily eaten by birds such as the Moorhen and Seychelles magpie robin, as well as by larger individuals of both Seychelles and Wright's skinks. They therefore tend to be found in areas with good protecting vegetation cover, into which they fall, jump or run when threatened. Very occasionally adult skinks are also attacked by seabirds, attempting to break the tail off for food. In these wooded habitats, they can reach a biomass of 26 kg per ha.
Seychelles skink.
Young Seychelles skinks spend their early days in dense vegetation for protection.
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Seychelles skinks will eat many types of food, including a wide range of insects and other small invertebrates, birds eggs, dropped fish from sea birds to cooked rice, bread, soft fruits (especially papaya or banana), coconut, and their own kind. Even dead giant millipedes are eaten if the segments have been broken open. It is a fairly regular sight to see a Seychelles skink wandering around wearing a neat collar. These collars are the dry body segments of giant millipedes, which have slipped over a foraging skink. Sometimes the collar is around the middle of the body and causes painful-looking abdominal bulging on either side of the constriction.
Seychelles skink bearing a Seychelles millipede body segment around its lower body which often causes temporary paralysis to the hindlegs.
Another unusual skink feeding habit is the deliberate knocking down of White tern and Lesser noddy eggs from the somewhat precarious nest sites on tree branches, and then rushing down to eat the contents of the smashed egg.
This Seychelles skink is in the throes of tossing an unguarded Lesser noddy egg from the nest to the ground, when it will then rush down at great speed to devour the contents before other skinks get there. The very large skink populations are among the highest densities recorded for any lizard anywhere in the world. Ball (2001) recorded densities from 260 individuals per ha in Morning glory habitat to 970 individuals in Pisonia/Fig forest, where the heaviest and longest individuals also occurred. High skink density is also associated with Lesser noddy numbers at nesting sites. During this time, food material in the form of bird faeces and disgorged fish and squid is accidentally dropped by adult birds or chicks. During the season, skinks accumulate fat deposits equivalent to about 50% of their lean dry weight, and these fat accumulations assist in maintaining the skinks during the months between noddy nesting seasons.
Skinks use elevated positions in search of their prey.
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Wright's skink Wright's skink (Mabuya wrightii) is endemic to the granitic Seychelles, but occurs on only four islands, all of which are sea-bird breeding areas. Apart from Cousine, they live on Frégate, Cousin and Aride. The overall total population on Cousine is about 10 000 individuals and a total biomass of about 911 kg (Ball 2001). Biomass ranges from 4.1 kg per ha in grassy areas to 51 kg per ha in Pisonia/Fig forest. Wright's skink is larger than the Seychelles skink, growing to 152 mm (snout-vent length) and reaching a total length of up to 400 mm, and can weigh up to 122 g. Hatchlings are about 125 mm in total length (about 46 mm snout-vent length). Colour patterns of the two species are similar except that the light lines flanking the dark lateral line present in both species is absent or less pronounced in the Wright's skink, which also has black, not white spots, on its back. Wright's skink also has a whitish chin, but the white generally extends further down the chest than in the Seychelles skink.
The rest of the undersurface is an orange-yellow colour, except for the tail, which is white with pale grey stripes. Wright's skink breeds all year round, laying eggs as does the Seychelles skink. Three to seven elongated white eggs are laid, each measuring about 24.5 mm x 19.5 mm. The diet of Wright's skink is the same as the Seychelles skink but, because of its larger size, Wright's skink is able to eat larger prey items, such as sub-adult Bronze geckos. Because of its restricted distribution and reliance on sea-bird breeding islands, Cousine is an important reserve for it.
Adult Wright's skink.
A Wright's skink with a body ring of the Seychelles giant millipede around its neck.
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Wright's skink is a robust lizard and a familiar sight in all the wooded areas.
A Wright's skink regrowing its tail.
Gardiner's skink Gardiner's skink (Pamelaescinus gardineri) is a secretive species that was only discovered on Cousine Island in 2008. A squat species with a shiny and smooth appearance, and shortened limbs, lives in the forest leaf litter, especially that of pandanus.
Gardiner's skink
Snakes Seychelles wolf snake One of the predators on skinks is the Seychelles wolf snake (Lycognathophis seychellensis). The species has been recorded from five other granitic islands - Mahé, Silhouette, Praslin, Aride and Frégate, and is endemic to the granitic Seychelles. The Seychelles wolf snake is non-poisonous, and kills its prey by squeezing it in its coils, preventing breathing. There are two colour patterns: a yellowish brown with faint spots dorsally, and a bright yellow belly; and a dark grey with distinct black spots dorsally, with a light grey belly spotted with dark grey and black. It is rare on Cousine, which hosts the dark-coloured form. The largest recorded has been a 1.4 m female.
Colour variations of the Seychelles wolf snake on Cousine.
Flower-pot snake The Flower-pot snake (Ramphotyphlops braminus), which has so far only been found on the Cousine flatlands and the North Hill, is small and feeds on soft bodied soil invertebrates, Reaching lengths of 150 mm, this thin, black, worm-like reptile has the distinction of occuring as a parthenogenic (reproduction without sexual union), all-female species. It is widespread in the tropics and sub-tropics, and is transported in containers of soil or plants with soil-bound roots. The species is quite harmless to humans. It lives under stones, logs or bark of rotting trees.
Yellow-bellied sea snake The Yellow-bellied sea snake (Pelamis platurus) is widely distributed from the east coast of Africa through the Indo-Pacific across to the west coasts of the Americas, although it does not appear to be common in any given area. It has been recorded on Cousine only once, when a specimen washed up on the beach (Lawrence 2007b).
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Yellow-bellied sea snake.
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OVERCOMING THE EXTINCTION OF EXPERIENCE: SEA BIRD HAVEN Overcoming the extinction of experience First setting foot on Cousine is an unforgettable experience. Besides being struck by its glimmering blue, gold and green, the first impression is one of clamouring activity. Sea birds are everywhere, gliding, hovering and endlessly chattering to each other. This experience is one that has virtually been lost on tropical islands of any size all around the world. Cousine almost lost it too, but for the concerted and sustained restoration programme which has almost returned it to its former glory before humans arrived. One concern worldwide is what has been termed 'the extinction of experience' (Miller 2005). This is the loss of the experience of wild nature wherever the modern human footprint falls. While we can engage in urban restoration, such activities normally only encourage the return of common and widespread species which have the ability to readily recolonize disturbed sites. Rarely do threatened species benefit from restoration programmes close to human habitation (Samways 2007). This is where Cousine has made an enormous contribution to global conservation. Not only has it now become a haven for many sea birds, and a refuge for some highly threatened land birds, but it has also given the world a unique experience of what it is like to walk among a throng of sea birds coming in to nest. We now consider these wonderful birds one by one.
Shearwaters A shipwrecked person, landing on Cousine Island during the night could hardly be blamed for jumping back into the sea with the sure certainty that the Island was haunted. The moaning and wailing calls of large numbers of the Wedgetailed shearwater (Puffinus pacificus chlororhynchus) is an eerie sound at night, during the breeding season (August to April), and chicks add to the sound. Shearwaters breed in burrows in soil or under rocks, and a single egg is laid. Foraging usually takes place at sea during the day. The birds leave the burrows before dawn and return usually after sunset, although shearwaters have been seen flying around their burrow areas during the night at Cousine.
Shearwaters often fly to the lights in houses, crash into walls and windows, and waddle around rooms and verandahs before eventually flying off again, often only at dawn. The Wedgetailed shearwater is about 450 mm long, is dark brown and has a pointed tail in flight.
Adult Wedgetailed shearwater at its nest entrance in a burrow under a granite boulder.
Adults preparing to leave for sea in the early morning.
Wedgetailed shearwater immature in its nest under a granite boulder.
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The size of the breeding population on Cousine has been estimated at 30 000 pairs, and occupies virtually all the granite areas of ridge and hill. Wedgetailed shearwater chicks and adults are in demand as food items by many Seychellois, and poaching of the young and adults has to be firmly controlled. This species, and the next, are now confined only to three rat-free and protected islands in the granitic Seychelles, the other two islands being Cousin and Aride. Audubon's shearwater (Puffinus lherminieri) is smaller than the Wedgetailed shearwater and is dark brown with a white belly. The breeding habits are similar to that of the Wedgetailed shearwater, except that it breeds all year round. Foraging, as with the previous species, is from the surface or underwater, the birds' entering the water from the surface or from short dives, possibly to depths of 20 m below the water surface. Small shrimps, squid and fish are eaten.
Audobon’s shearwater.
Tropicbirds White-tailed tropicbird White-tailed tropicbird (Phaeton lepturus) is an elegant graceful flyer, and catches fish at sea by first hovering and then plunging with half closed wings. It has a cushion of air cells under the skin in front of the body which absorbs the shock of diving impact. This subspecies is confined to the Indian Ocean, with other subspecies spread through other tropical oceans.
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The White-tailed tropicbird is about 440 mm long, and is white with two black patches on each wing. The beak is yellow and the two elongated central tail feathers are white.
White-tailed tropicbird adults.
A rare case of a White-tailed tropicbird nesting on the open beach. It breeds all year round on Cousine, laying a single egg under shelter of tree trunks, rock overhangs and crevices or between tree roots. Occasionally the tropicbird will nest in holes or crevices in trees and also among the fronds of coconut palms, or high on sheer cliff faces. They are usually ground nesters in areas where there are no rats. The numbers of birds on Cousine have been estimated to be at least 2 500 pairs, being a rat-free island.
White-tailed tropicbird: progressive development of the hatched chick.
Adult and newly hatched White-tailed tropicbird chick under a rock overhang. White-tailed tropicbird egg.
White-tailed tropicbirds contesting a nest site.
Newly hatched chicks; all fluff. A giant tortoise enjoying the shade with an immature White-tailed tropicbird
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The first primary wing feathers just making an appearance.
The development of wing covert feathers.
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The development of primary wing feathers becomes obvious.
The wing coverts, primaries and secondary feathers are now marked.
Red-tailed tropicbird Although breeding on Aride Island, Red-tailed tropicbirds (Phaethon rubricauda) do occasionally appear on Cousine, but as yet have not been recorded breeding.
Frigate birds
Last of the fluff about to be replaced by adult feathers.
Ready to leave the nest for a life at sea.
The emblem on Cousine Island's logo, the Greater frigate bird (Fregata minor), occurs in small numbers over the Island on most days. A magnificent flier, this species, as well as the Lesser frigate bird (Fregata ariel), obtains some of its food by robbery. It steals eggs and young of other sea birds, or chasing successful fishing birds, such as terns, in an attempt to make them disgorge their prey. Frigates are quite capable of catching surface fish by swooping down and scooping the prey up with their beaks, but the birds do not have the waterproof oils in their feathers that many diving birds do. They must therefore be careful not to accidentally fall into the sea, as they are likely to drown. The Greater frigate bird male is all black, lacking the white patches in the armpits of the Lesser frigate bird male. The Greater frigate bird female has a white breast and throat, and the Lesser frigate bird female has a white upper breast but a black chin and throat. The Greater frigate bird is 950 mm long in contrast to the 760 mm long Lesser frigate bird. Neither species breeds in the granitic Seychelles.
An adult White-tailed tropicbird leaving its nest for the sea Greater frigate birds silhouetted against the sky above the Island.
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Greater frigate birds occasionally land in trees on the west coast.
Lesser noddy on a nest in a Euphorbia tree. Nesting material consists of leaves from Pandanus, Pisonia and Small-leafed fig.
Lesser noddy Cousine Island is home to an estimated 89 000 breeding pairs of the Lesser noddy (Anous tenuirostris tenuirostris). This is equivalent to about 3 420 breeding pairs per hectare. On the only other thee granitic islands on which it breeds, Aride, Cousin and Frégate, its population sizes are 121 400 pairs and 10 000 pairs respectively. It is also distributed in the Cargados Carajos Shoals (340 km north-east of Mauritius), in La Réunion and the Maldives. The noddies often feed far out to sea, congregating over shoals of small pelagic fish. They do not plungedive but feed by hovering above the surface before swooping down to pick up their prey. Noddies can swallow and then regurgitate their food, so they can forage far more widely than those birds which have to carry their prey back to their young in their beaks, as White terns have to. Dropped fish and faeces from noddies enrich the island soil, and form a food source for plants, birds, skinks, flies and beetles. The Lesser noddy is thus considered to be one of the keystone species in the ecology of Cousine. Noddies nest in trees from May to September, laying single eggs on flattish nests made of fallen leaves, particularly of the Pisonia tree and damp kelp, which is picked up off the beach or out of the sea.
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A Lesser noddy sitting on a newly-hatched chick which is just visible behind the egg shell.
Lesser noddy nest and egg.
Their habit of tree nesting, and their use of Pisonia as a nesting tree, results in several hundred birds dying annually. Pisonia has numerous sticky, hooked fruits (see p.58) check in which the birds sometimes become so entangled that they are unable to fly and die of starvation, or are killed by predators, such as the Dark ghost crab. Although the sight of tangled, immobile birds is distressing, the Lesser noddy and Pisonia have existed together for thousands of years, and even though the Pisonia kills a small percentage (probably about 3%) of noddies, the birds benefit by having trees in which to nest. In turn, the trees benefit from the rich food represented by the noddies' faeces, and dropped sea food. Pisonia has soft wood, and sometimes the weight of a noddy nest breaks off or cracks a small branch. Even though a nest may only have moved 50 cm from its original position after a branch has cracked, noddies sometimes will not feed their chicks after this has happened. In other cases, even when the chick has fallen to the ground, the adults will continue to feed their chick, even though in such a situation the chick is highly vulnerable to predation from crabs and other predators. Noddies can benefit in the long term from a branch breaking off, as such branches readily root and send up more stems, offering more nesting sites. Two of the main predators of Lesser noddy eggs are the Seychelles skink and especially the Seychelles fody. The adult noddies rarely leave their nests exposed except when they are disturbed by humans passing below the trees in which they are nesting. The fody follows people when traversing the island during the noddy nesting season and rapidly take the opportunity of eating an exposed egg. This is the main reason why human presence is generally restricted on the North hill and South ridge from May to October.
Lesser noddy egg predation by the Seychelles Fody.
Fledged Lesser noddies congregate on the beach in their hundreds prior to their departure.
Brown noddy The Brown noddy (Anous stolidus pileatus) is widespread in the IndoPacific, and there is a population of about 600 pairs on Cousine. These birds nest on granite boulders, either bare or covered with vegetation, normally Beach morning glory, or they nest in Pandanus and coconut palms. Nesting takes place from mostly May to September, and the birds build somewhat indifferent nests of sticks or leaves and sometimes small pebbles, or make no nest at all (Ramos et al. 2006). Only one egg is laid. The feeding habits are similar to those of the Lesser noddy.
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The Brown noddy nesting habitats are mainly on open rocky areas.
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A Brown noddy nest with very little nesting material.
The roughly built nest of the Brown noddy.
A Brown noddy nest made of leaves of Smallleafed fig, Fire euphorbia and pieces of twig.
At the rock nesting sites, Brown noddies are usually gregarious in small 'clans'.
A Brown noddy nest of Pandanus leaves.
Coconut palm crowns are also used by pairs and groups of Brown noddies for nesting if there is available space. Brown noddy chicks are normally dark brown in colour when they hatch, although a small percentage white when they hatch, and as they develop, undergo a colour change to brown.
Development of a white variety of a Brown noddy chick, from a hatchling through to a normal coloured fledgling.
White tern
Newly hatched Brown noddy chick with the normal brown hatching colour.
Another tree-nesting seabird is the superbly graceful White tern (Gygis alba monte), one of the emblems of the Seychelles. This monte sub-species occurs only in the Seychelles, Madagascar and Mascarenes. Although generally called the Fairy tern, this common name really applies to another tern species. Since the White tern is the only pure white adult tern in the world, its name is appropriate. The species lives permanently on Cousine, breeding the whole year round. The population has been conservatively estimated to be about 3 000 pairs.
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Breeding sites vary from a rock to a hollow or crack on a bare branch, and even a hollow coconut husk. Some nesting sites appear very precarious, and include the top of a broken off branch or the dry base of a fallen but hanging coconut leaf. Amazingly, they will even lay their eggs on a steeply leaning coconut palm trunk or precariously on a coconut palm frond. No nest is built, the single egg being laid straight onto the bare
Adult White terns.
The ultimate grace…a White tern gliding.
A brooding White tern with fluffed-out breast feathers indicating that the bird is sitting on an egg.
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At times, white terns are very affectionate to each other.
A variety of White tern nest sites.
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The eggs are constantly under threat, and if they are left unguarded for too long, skinks or birds such as the Seychelles fody, will destroy them. Skinks will try to push the eggs off branches with their snouts. If successful, the skink rushes down the trunk to the ground to get to its meal before one of his numerous fellow skinks get there first. Because of the high skink density on Cousine, an egg is likely to be completely devoured within a few minutes after being broken. The Seychelles fody, when finding an untended egg, simply punches a hole into the egg and eats the contents. Hatchlings of the White terns are brownish, and as they grow older become whiter with brown bars on their wings and body. With maturity, the birds develop a snowy-white plumage.
A White tern returns to its chick with fish in its beak.
White tern chicks on the exposed leaning trunks of coconut palms.
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A young chick in a secure position in the fork of a tree.
A young chick clings to a coconut palm frond.
Family comfort: an adult White tern sitting on and protecting its chick.
A chick at the end of a dry fallen coconut palm frond.
The start of the colour change in the young White tern chick.
A precarious nest site on a cut bamboo stump.
A meal of flying fish.
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The immature bird with the last remnants of the brown hatchling colouration. At this stage, short flights are attempted but it is still dependent on its parents for food.
Bridled tern Another sea bird that nests on Cousine is the Bridled tern (Sterna anaethetus), which has a small somewhat irregularly breeding population of probably less than 50 pairs. Nesting takes place at about eight month intervals, and nest sites are under boulders or in crevices in rocky, exposed areas. Dense nesting colonies are not formed, and breeding pairs are usually spaced well apart, sometimes in loose colonies. Fishing is carried out close to shore, the birds hovering low over the sea and dipping to pick up food items near the surface. On Cousine, nesting areas are on the Ridge and on the west side of the North hill.
A pair of Bridled terns.
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Courting Bridled terns
Sooty tern The Sooty tern (Sterna fuscuta nubilosa) is the most truly oceanic species of all the terns. It has also been one of the most exploited of sea birds, with over 1.5 million pairs having been lost in the Seychelles. The Mascarene Islands have also been similarly exploited (Feare et al. 2007). On maturing and taking to the air, it can spend four years airborne over the oceans before returning again to land. It used to nest on Cousine but was subject to egg harvesting. This, possibly combined with general disturbance and habitat changes, led to a cessation of breeding by 1971. The original nesting sites, all over-grown with mainly Coromandel, were located in 1998 and an active programme of habitat management, which involved the removal of Coromandel and other plants to about 30% ground cover, then followed. The benefits of this programme, and the reappearance of open ground for nesting, came to fruition in April 2003, when the Sooty terns returned to nest after over 30 years absence. Nevertheless, there are still concerns for its overall future in the face of climate change and over-exploitation of its tuna food base (Feare et al. 2007).
Fully fledged Sooty tern about to leave the Island after which it will only return to land again to breed when fully mature, a few years later. Note the seeds of the Little sticky seed attached to the head and neck.
Adult Sooty tern.
An adult Sooty tern protecting its newly hatched chick from the hot sun.
Other members of the gull family which occasionally visit the Island include the Arctic skua (Stercorarius parasiticus), Gull-billed tern (Geochelidon nilotica), Greater-crested tern (Sterna bergii), Lesser-crested tern (Sterna bengalensis), Black-naped tern (Sterna sumatrana), Roseate tern (Sterna dougalli) and Common tern (Sterna hirundo).
Newly hatched Sooty tern chick being fed.
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AQUATIC AND SHORE BIRDS
Herons and Egrets The Cattle egret (Bubulcus ibis sechellarum) does not breed on Cousine, but small groups of up to 20 may be seen foraging in the open secondary areas, having flown from Cousin or Praslin Islands. It has been recorded all year round. While there have been doubts as to the validity of the subspecies, recent work has indicated that there are differences between breeding colours of cattle egrets in the Seychelles and those elsewhere, suggesting that it may be a separate species.
Cattle egret, treading carefully.
The Moorhen The Moorhen (Gallinula chloropus) was relatively uncommon before 1994 although there are records of them being caught and eaten by island staff in former years. Also perhaps in response to the building of well-distributed, permanent watering points for giant tortoises and small catchment baths under water taps, there has been a dramatic increase in the Moorhen population. Where previously, they were confined to a small swamp in the drainage line, they are now spread throughout the coastal plain and onto both the North Hill and South Ridge. Over 100 birds are present on the Island, and breeding takes place throughout the year. Moorhen numbers are controlled through a very strong clan territorial system and the resulting natural selection of the strongest clan members. Territory boundaries are continually being contested by not only the territorial male, but also by his entourage of females who often make a loud noise rather than physical contact. Boundary conflicts can be serious affairs, with one of the combatants sometimes succumbing as a result of the conflict.
The rocky intertidal zone is home to the Greenbacked heron (Butorides striatus digens) which is seen throughout the year on the rubble flats at low tide and, in particular, boulders near the sea edge. It breeds in trees on Cousine. The Grey heron (Ardea cinerea) has been seen a few times on the coastal plain, but does not stay for long.
Adult and immature Moorhen. Territory sizes vary, depending on locality and food supply, which, in turn, also determines the clan size. The largest clans are on the lowland plain where there is an abundant food supply related primarily to the availability of kitchen scraps as well as wild resources. These lowland territories are far smaller in size than those on the elevated areas. Grey heron.
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The nests are usually built on or close to the ground, but can be placed up to two meters above ground in a shrub or tree. There are up to 18 eggs per clutch. All these eggs are not those of a single female but are contributed to the nest by the other females within the clan. As incubation proceeds, the clutch size is reduced by eggs being removed from the nest and eaten by the adult clan members. Mortality of hatchlings is also high with usually only one or two chicks surviving. Moorhen adults and subadults take turns at guarding and feeding the chicks, and take food to the chicks over some distance. Sometimes a quivering, begging small chick, crouched on the ground with wing-stubs spread in supplication, can have up to four adults trying to feed it.
Moorhen on its nest in a Euphorbia bush just above the ground.
Two newly hatched chicks peering out from under the adult.
The immature or subadult birds within the clan will invariably be persecuted by the adults and chased out of the clan. During this period of clan unrest some immature birds escape the persecution by taking up residence with humans. They will spend periods of time within houses and will often spend the night to escape the clan conflicts. Some of these young birds will be accepted by other clans, others will form new territories on the remoter parts of the island, but the majority are hounded onto the beaches where they are forced to emigrate to other, nearby islands. From records of ringed moorhens, it is known that at least seven have left Cousine, of which five have been found on Cousin and two reached Praslin. The value of Cousine's population is as a source population for inter-island distribution of the species, although tragically, the dispersers are often killed and eaten by people. Crabs, skinks, other birds, and even humans are warned off, or chased, while defending its nest, and the bird makes curious, low growling sounds. Moorhens are aggressive to the point of catching and killing smaller birds such as the Lesser noddy, Madagascar and Seychelles fodies, Barred ground dove and Turtle dove, especially if these birds impinge on a feeding area or are close to a nesting site. En masse, moorhens will even attack larger birds such as the White-tailed tropic bird, and formerly, domestic fowl. Moorhens eat a variety of foods, from vegetation such as grasses and sedges, to seeds, fruits and
Moorhen in search of invertebrates.
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Moorhens are particularly fond of cultivated, ripe bananas.
Ruddy turnstones.
Crab plover Plovers, sandpipers and related shore birds Characteristic of the beaches are numbers of shorebirds, none of which breed on Cousine. These include rare migrants and regular migrants. The rare migrants include species such as Common ringed plover (Charadrius hiaticula), Grey plover (Pluvialis squatarola), Pacific golden plover (P. fulva), Greater sandplover (Limosa leschenaultii), Bartailed godwit (Limosa limosa), Curlew sandpiper (Calidris ferruginea), Little stint (C. minuta), Temminck's stint (C. temmincki) and Curlew (Numenius arquata), while more regular visitors include the Lesser sandplover (Charadrius mongolius atrifrons), Common sandpiper (Tringa hypoleucos), Greenshank (Tringa nebularia) and Sanderling (Calidris alba). The most frequent regular visitor is the Ruddy turnstone (Arenaria interpres) with flocks in excess of 100 birds at times, and Whimbrel (Numenius phaeopus), up to 50 in flocks, which not only forage on the beaches, but also on the flatlands and in the more open granite areas.
Another interesting and elegant shore bird is the Crab plover (Dromas ardeola), which feeds on ghost crabs (mainly the Horned ghost crab) during evenings when this crab emerges to forage. The crabs are chased and pecked until they are immobilized. The plover then picks the crab up by a leg, shakes the crab until the leg is broken off, swallows the leg and thus continues until all legs have been devoured. The carapace is then pecked and pieces are broken off and eaten until the whole crab has been ingested. If the crab was killed on soft sand, the plover carries the carapace to hard sand in the intertidal zone where the crab dismantling process is easier. Crab plovers, together with Turnstones, also forage on the rubble flats at low tide.
Crab plovers feeding on the exposed reef at low tide.
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A TRULY SUCCESSFUL STORY: ENDEMIC LAND BIRDS Seychelles blue pigeon Fruit pigeons are not particularly common in the Seychelles, although globally widespread. Their diet includes fruit from a variety of trees, perhaps the favourite being figs. A denizen of forest, the Seychelles blue pigeon (Alectroenas pulcherrima) is frequently encountered on Cousine, and has probably increased in the last 20-30 years with the increase in size and number of fig trees on the island, and a cessation of hunting. At least 75 birds are now believed to be present.
The Seychelles race appeared to predominate on Cousine in the 1970s. It was believed that the Island was one of the few on which hybrids did not overwhelm the native race as was the case on Praslin and Mahé. Ringing done on Cousine, followed by recording wing measurements showed that the population is probably hybrid, with strong picturata tendencies. A few rostrata-like forms may still be present. The dove population is one of the only two areas left (the other being on Cousin) in which the Seychelles turtle-dove could have been rescued. Now the populations are likely to have been subjected to irretrievable genetic contamination.
Seychelles blue pigeon Its fragile-looking, stick nest is built in trees, including Casuarina, Bamboo, Fig, Takamaka and formerly Topflower clausena which is no longer on the island. Breeding is in March and October with nests being built from 2 m above the ground to 25 m high in mature large trees. It is not unusual to find the occasional adult and subadult bird looking very forlorn under the influence of eating overripe fruit of both the fig species mainly between April and July. When found in this condition they are best just left alone, as any attempt to assist them through this condition seems to stress them.
Madagascar turtle dove.
Seychelles turtle dove The story of the Turtle dove (Streptopelia picturata rostrata x S.p. picturata) is one extinction of a subspecies. The population of Turtle dove on Cousine was at one stage said to consist of the Seychelles turtle dove (S. p. rostrata), the Madagascar turtle dove (S.p. picturata) and hybrids between the two.
Seychelles turtle dove.
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adult birds were translocated to Cousine. Two males and a female were received from Frégate in October 1995 but the female disappeared and was later found dead in her nest box after three months, and suspected of having been killed by a White-tailed tropic bird seeking a nesting site. The surviving males were joined by four more birds in November 1996: one female from Cousin, two females and a male from Frégate.
Hybrid turtle dove
Seychelles magpie robin The story of the recovery of the Seychelles magpie robin (Copsychus sechellarum) is one of the most successful in bird conservation to date (Komdeur 1994,1996, LeMaitre 2002, Norris and McCulloch 2003). The bird formerly occurred on Mahé, Praslin, La Digue, Marianne, Felicité, Aride and Frégate islands. Loss of habitat and predation by rats and cats led to a drastic decline in numbers and range. By the early 1960s, the whole population was confined to Frégate, which had a resident cat population. Unfortunately, magpie robin numbers did not, as expected, increase following eradication of the cats, and by the late 1980s, only around 20 birds survived. With the species close to extinction, there was clearly a need for swift action. A recovery programme was initiated by Birdlife International and it was considered of paramount importance to first increase overall numbers and productivity, bearing in mind that females usually only lay one egg per breeding attempt. Once successful breeding had been achieved, birds would be translocated to other predator-free islands to establish satellite populations as a species is extremely vulnerable when confined to only one location. Following daily supplementary feeding and supplying nest boxes to all territories on Frégate, positive signs of recovery were evident, and the population increased to 40 birds by March 1994. At this time, only three other granitic islands remained free of rats and cats: Aride, Cousin and Cousine. Their combined area is a little over half that of Frégate, which is approximately 219 hectares. Between October 1995 and November 1996, seven
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The arrival of the first Seychelles magpie robins on Cousine (October 1995).
Seychelles magpie robin holding cage prior
The oldest magpie robin in the Seychelles. This male, known affectionately as the 'Old Man', was the first bird to be released on Cousine, and was the pioneer of the Cousine population. At the time of his death in 2001 he was 16 years old.
All birds were intensively monitored on a daily basis and fed, in addition to their natural diet, with supplementary food at fixed feeding/water stations within each of the established territories. Twenty six nest boxes were established well above the ground on tree trunks in suitable areas.
Seychelles magpie robin showing coloured plastic rings on the left leg for individual recognition and an aluminium numbered ring on the right leg
Intensive care of Seychelles magpie robin. One pair began breeding at the end of January 1997 and by 31st December 1998, 11 chicks had been successfully reared to independence. During early 1999, there were 14 birds on the Island. Between 1999 and 2007 the population had increased to 39 birds, holding territories across the whole island. During this time there have been fluctuations in numbers due to emigration to other islands and mortality. The vegetation rehabilitation programme has been an integral component of the success of the programme. It is usually difficult to tell the difference between individual male and female adult birds just by looking at them. As a component of the Birdlife International Seychelles Magpie Robin Recovery Programme, all Magpie robin chicks are blood sampled for sex determination and ringed in the nest with specific colour ring combinations so that they may be easily identified and closely monitored.
Early studies of this species reported that the clutch size was two eggs, although since the late 1980s only two or three females have been known to do this. However, on 17 December 2001, it was discovered that a female on Cousine had laid two eggs and both had successfully hatched. Most breeding attempts today involve only one egg.
Seychelles magpie robin 'twins', the first recorded in the Seychelles. Just prior to fledging, the chick is removed from the nest, its biometrics recorded, a blood sample collected for sexing analysis and the bird ringed and is placed back in the nest. Food and water are provided on skink-proof tables, mainly because food thrown on the ground is quickly eaten by skinks. The food supplied consists of specially formulated soft-billed bird pellets.
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Indian cockroaches (Pycnoscelus indicus) are also caught in the vegetation litter layer during the daily feeding rounds and are offered to mainly breeding females. This is an interesting case of an invasive alien species being a major resource for a highly threatened bird species (LeMaitre 2002). A feeding-and-water table is positioned at a suitable site in each of the magpie robin territories. 7 days
13 days
Seychelles magpie robin feeding-and-water table.
Development of the Seychelles magpie robin hatchling.
3 days
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17 days
Adult Seychelles magpie robin feeding fledgling.
Unless great efforts are made in the Seychelles to eliminate this scourge they will lose one of its most charismatic and colourful endemic land bird species, as well as many other endemic species. Cousine, being a rat-free island, therefore continues to play an extremely important role in the continued preservation of this threatened bird. Indeed, Cousine has played a role in this species being downlisted from the IUCN Red List status of Critically Endangered in 2000 to Endangered in 2007.
Immature Seychelles magpie robin in moult.
Seychelles magpie robin looking, for and listening to, its prey among wood litter.
Courtship display by a male Seychelles magpie robin. Since August 1995, Frégate's wildlife has been exposed to a new and very damaging threat, rats. In 2001, an extensive de-ratting programme was initiated and the island was cleared of rats.
Seychelles warbler The insectivorous Seychelles warbler (Acrocephalus sechellensis) is known only from the Seychelles, where, in the middle of the last century it went through a severe genetic bottleneck (Brouwer et al. 2007). In 1870, it was recorded on Marianne, and on one other island, which was either Cousin or Cousine. Between 1910 and 1920, both islands were planted to Coconut palms which required clearing of any competitive vegetation. This clearing resulted in considerable loss of indigenous vegetation and subsequent loss of the bird from Marianne and possibly Cousine. Certainly, the bird was present on Cousin in 1938 but was rare and under pressure from further Coconut palm planting, resulting in only 26 birds surviving in 1959 (Komdeur 1994). From this initial population of 26, successful management of Cousin enabled the population to increase to about 320 birds, the Island's estimated carrying capacity. Six birds were then introduced to Cousine during the 1960s, but these did not survive, possibly because of unsuitable habitat at the time. In September 1988, 29 warblers were translocated to Aride island, and in June 1990, 29 warblers were translocated to Cousine. By June 1991, the populations on these islands had increased to 165 and 43 respectively, and by May 1995, the total population on Cousine was estimated at about 80, established in 24 territories. By 2007, the total population estimate was 350-400 birds. Nevertheless, the species remains on the Red List as Vulnerable until such a time that we can be assured that its future is secure.
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Sex ratios at hatching are influenced by territory quality. In territories with poor food and cover, males are produced, while in good quality territories female offspring predominate. Interestingly, the bird even occasionally forages for insect prey on the shore. An overall ratio of one male to one female was found during 1995 on Cousine. Seychelles warblers start nest building during highest rainfall and lowest temperature regimes and usually lay only one egg (Komdeur et al. 1998, 2004, 2005). Seychelles warbler nestling just prior to its leaving the nest.
Seychelles white-eye The Seychelles White-eye (Zosterops modestus) is a very rare and threatened endemic to the Seychelles. It occurs naturally on Conception and Mahé islands, where is appears to be remarkably tolerant of alien vegetation. This is possibly because it is primarily an insectivore, with alien plants being a rich supply of various insects and fruits. Seychelles warbler, a major breeding success on Cousine.
One of the first Seychelles white-eye birds to arrive on Cousine, in its reception aviary. This Seychelles warbler has benefited from an alien plant, having used cotton fibres for making its nest.
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Between 7th and 19th July 2007, a total of 20 individuals of the Seychelles white-eye were introduced onto Cousine from Conception (Jolliffe et al. 2008). Prior to their release into the wild, they were placed in a specially constructed aviary erected around a planted Bwa dile (Tabernaemontana coffeoides) tree. This tree produces seed pods on which white-eyes will feed.
The aviary was positioned among Pisonia and fig branches, as well as those of Bwa siro (Premna seratifolia), so as to provide a natural setting. Supplementary feeding of the captive birds included honey smeared onto a stick and sprinkled with termites, free ranging termites, and a commercially-produced nectar formula from drip feeders. The birds were released after being settled in the aviary for 1-2 days. Immediately after release most individuals flew immediately to the nearby T. coffeoides trees and began feeding on its berries. However, the resident Seychelles warblers and Seychelles fodies soon chased the whiteeyes away and out of their territories. The newlyreleased birds then began to explore the whole island, mostly settling down among the large Ficus reflexa trees on the North Hill. In this forest, the birds foraged for insects and spiders, especially the Seychelles cottony cushion scale insect (Icerya seychellarum) which is attended by ants, especially the Big-headed ant, and so encouraged to large population levels.
pass food, mostly invertebrates such small caterpillars and cottony scales, but supplemented with fruits of F.reflexa and T. coffeoides. Interestingly, fledgling feeding is shared by five of the adult birds, a dominant pair, a subordinate pair and a subordinate male (Jolliffe and Henwood 2008). All the indications are that the white-eye introduction has been immensely successful, with the birds also benefitting from the restoration of the plain with trees. Cousine is providing an extra safety net for survival of the bird in the Seychelles as a whole. Thus, Cousine is playing a role in the species being downlisted on the IUCN Red List from Critically Endangered in 2000 to Endangered in 2007.
Within a few weeks of introduction to Cousine, the Seychelles white-eye had begun to build nests The introduced Seychelles white-eye took readily to nectar feeders provided for it. Within a few days of release, the white-eyes were beginning to establish territories, and by early August, pairs were starting to form, and nests being built. One of the challenges faced by the introduction programme is that two of the first white-eye chicks were killed by Seychelles magpie robins. Probably, this is the result of predation by the magpie robin, rather than competition for food resources, as the magpie robin has also been observed to feed on young Seychelles fodies. Protection was then given to the fledglings by placing them in a holding cage made of a wooden frame and chicken wire, and suspended in a tree. Perches were provided inside the cage where the fledglings waited for the adults to
One of the first Seychelles white-eye chicks being reared on Cousine in April 2008. Unfortunately this chick and one other was killed by Seychelles magpie robins.
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Seychelles sunbird The endemic Seychelles sunbird (Nectarinia dussumieri) is the only representative of the sunbird family in the granitic Seychelles. The species is widely distributed in the Seychelles and has habits characteristic of most sunbirds. It is a lively, noisy bird feeding on flower nectar and small insects. The nest is pendulous mainly of grass, rootlets, cotton fibres and spider webs, usually hanging at the end of a branch. A single egg is laid. The breeding season is usually between October to March, but occasionally breeding takes place during other months. There is no estimate yet of the numbers on Cousine.
It forages extensively on tree-trunks, examining crevices and spaces under bark for food. The birds are alert and curious, entering houses freely to see what food can be garnered from the floor, table or plates. They will even enter an open fridge and cupboards where there are plastic storage boxes and bags, in anticipation of the containers being opened. Sometimes they are sufficiently resourceful to open the containers themselves.
Seychelles sunbird male.
Seychelles fody The Seychelles fody or Tok-tok (Foudia sechellarum) occurs only on Aride (where it has been introduced), Denis, Frégate, Cousin and Cousine islands, with a population introduced to D'Arros Island in 1965. It is classed as a threatened species. It is abundant on Cousine, with 388 individuals having been ringed from 1995 and 1997, and an estimated population size of 450 at the end of 2007. At that stage, it was believed that all the available habitats were occupied. Although conspicuous on the coastal plain, most nesting is in the granite areas where its untidy grass nest is built in trees and shrubs from 0.2 m to 10 m above the ground, but usually between 3 m and 4 m. The species is omnivorous. As with many other island fauna, it will eat whatever food is available, from fruit to kitchen leavings.
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Sequence of a Seychelles fody opening a plastic container
Fodies breed all year round, with a peak in September and October. Two to three eggs are laid, but it is unusual if more than one hatchling survives to fledge. They have unusual brood provisioning behaviour, where the male parents exclusively provision male fledglings and female parents provision female fledglings (Vega et al. 2007).
Female Seychelles fody
A submissive immature Seychelles fody showing the small white wing patch.
Male Seychelles fody
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THE WELCOME AND THE UNWELCOME:VAGRANT AND ALIEN BIRDS Vagrants to Cousine Migrant birds are under threat in many parts of the world. Cousine at least provides a safe resting place for some of these. We met some of them as shore birds in an earlier chapter, but there are also some migrant land birds that occasionally find shelter on Cousine. The Honey Buzzard (Pernis apivorus) was seen for the first time on Cousine in June 2007. The Hobby (Falco subbuteo) is a small falcon and a rare visitor to Cousine, where it has been seen to feed on White terns. The Red-footed kestrel (Falco vespertinus) is another occasional visitor and feeds on Seychelles and Wright's skinks which it captures in the open areas. There are also records of Eleonora's falcon (Falco eleonora), also feeding on White terns, and sightings of the Black kite (Milvus migrans migrans). Other vagrants include the European cuckoo (Cuculus canorus), Asian lesser cuckoo (Cuculus poliocephalus), Little swift (Apus affinis), European Swallow (Hirundo rustica), European golden oriole (Oriolus oriolus), White wagtail (Motacilla alba), Yellow wagtail (M. flava) and the Tree pipit (Anthus trivialis).
Primarily a ground feeder, it is found in open areas and especially likes pigweed seeds as a food source. It does not appear to be a problem on Cousine, especially as it forages on the ground in open sunny areas, a different habitat from most of the endemic land birds.
The Barred ground dove
The alien Barn owl The Barn owl (Tyto alba affinis) was introduced to the Seychelles by the Seychelles Department of Agriculture during 1951 and 1952 to control rats. Up to 1994 there were no verified sightings on Cousine, although beheaded Lesser noddy and white tern carcasses, first recorded during March 1993, were evidence of the owl's presence. Calls were heard during May, July, October and December in 1995, from January to April, and in August and September 1996. Several individuals have since been destroyed on Cousine, and may have flown over from Cousin and Praslin.
Yellow wagtail
A resident alien: the Barred ground dove The Barred ground dove (Geopelia striata) is an introduced species, native to Asia.. It probably reached the Seychelles in the late 18th century, but it is not known at what stage stage it colonized Cousine.
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The Barn owl is a danger to Cousine's rare endemic birds
Tropical Island Recovery: Cousine Island, Seychelles.1st edition. By Michael Samways, Peter Hitchins, Orty Bourquin, and Jock Henwood. Published 2010 by Blackwell Publishing Ltd.
Threats from the Indian mynah The Indian mynah (Acridotheres tristis) is believed to have been introduced to the Seychelles late in the 18th century from India via Mauritius. Mynahs are active predators on the eggs and hatchlings of other birds, and for this reason, are destroyed on the Island whenever they appear. Trapping of Indian mynahs on Cousine started in 1992, when six were destroyed. However, by the end of 1994 their numbers had definitely increased, even though eight had been destroyed that year, and it was not unusual to see groups of up to six birds. A population of 20 was estimated. By November 1996 an estimated four pairs were present on the island. Today the Island is largely free of this menace, mostly through continual control measures. It is believed that the birds fly across from Praslin to repopulate Cousine, resulting in the need for an ongoing control programme.
Although concerns have been voiced regarding the possible interbreeding of Madagascar and Seychelles fodies, no evidence of this has been noted. The Madagascar fody is primarily a seed eater. Although the Madagascar fody has been described as an alien to the Seychelles (Sinclair and Langrand 1998), there is the possibility that it may in fact be indigenous to the Seychelles. The breeding plumage of the male is characteristically bright scarlet above and below although some males fail to develop the red on the belly which remains brown. In January 2000, a single male with a golden yellow plumage was seen on Cousine for the first time. In April 2000 a second flavistic male was observed followed by a third male in October 2001.
Indian Mynah
The male of the Madagascar fody is bright scarlet with a black eye-stripe, while the sparrow-like female is brown with a black spotted back.
Madagascar fody The Madagascar fody or Cardinal (Foudia madagascariensis) was introduced to Cousine in 1958. During a dry spell in October 1994, flocks in excess of 200 birds were feeding on the coastal flats.
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The rare bright golden yellow form of the male Madagascar fody on Cousine island.
Two male Madagascar foodies entangled in the sticky and spiked panicles of Pisonia. Left like this they would not survive.
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VISITING MAMMALS TO COUSINE Seychelles fruit bat A winged visitor to Cousine through most of the year, but especially November to February, is the only nonhuman land mammal using the Island, the endemic Seychelles fruit bat (Pteropus seychellensis). It usually flies from Praslin and Cousin to Cousine to feed on the fruits of trees (mainly figs, but also Takamaka, Pacific almond and others). Owing to its fruit-eating behaviour and its mobility, it functions as a seed disperser, although the dynamics of this process have not yet been quantified. It usually appears about an hour before dark, although sometimes earlier, and leaving before dawn. It has also been recorded in low numbers arriving on Cousine directly from Aride, with one record of a bat arriving from Frégate Island. Up to 500 bats may be seen flying to Cousine from Praslin, Cousin, and La Digue during the late evenings, but to date never from Mahé. At times, when there is an abundance of fruit, the bats roost on the high trees on the North hill and the South ridge, but usually only for limited periods of one to ten nights, before returning to their normal roosts elsewhere.
Seychelles fruit bats roosting in Pisonia on the North hill.
Fruit bats are eaten in virtually all the regions in which the genus Pteropus occurs, from the South Pacific to the Indian Ocean islands, but not, for some reason, on the African mainland. On Mauritius and La Réunion, the local species has become extinct because of this. The island populations are vulnerable to exploitation and the removal of large roosting trees. Bat damage to fruit crops gives landowners an excuse for killing the bats, threatening the species further. Cousine therefore plays a supporting role in maintaining the species albeit on a temporary basis.
Fruit bat mortalities occur through electrocution from power lines on both Mahé and Praslin.
During 1977, it was estimated, following counts, that about 2 500 fruit bats lived on Praslin and the neighbouring islands, while about 10 000 bats were believed to live on Mahé. The current status in the Seychelles is unknown. Copulation takes place primarily during June and July, and most young are born in November and December. Adult bats weigh up to 600 g, and are eaten by the Seychellois. Tropical Island Recovery: Cousine Island, Seychelles.1st edition. By Michael Samways, Peter Hitchins, Orty Bourquin, and Jock Henwood. Published 2010 by Blackwell Publishing Ltd.
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Visitors in the sea Of the sixteen species of marine mammal (all whales and dolphins) known from the Seychelles waters, the Bottlenose dolphin (Tursiops truncatus) is the most frequent visitor around Cousine, with school sizes varying from three to eleven animals.The Bottlenose dolphin reaches 3.5 m in length, and feeds mainly on fish and squid by driving fish ahead and then encircling them. Other rare sightings are those of the Spinner dolphin (Stenella longirostris) and three visits by Humpbacked whales (Megaptera novaeangline) in recent years. All species of dolphins and whales are protected in and around the Seychelles. In the 19th century, Yankee whalers operated all year from their Seychelles base, but closed down around 1865. In 1913, a whaling station was opened on St. Anne and during its brief operation took about 450 Sperm whales, mostly off Denis and Bird islands.
The black shadow: alien mammals In the granitic Seychelles, introduced wild and domesticated animals have contributed greatly to the demise of plant and animal communities. The tenrec (Tenrec ecaudatus) was introduced to the Seychelles from Madagascar in the 1800s and is now fairly common on Mahé and Praslin. The animal is a delicacy in Madagascar but is seldom eaten in the Seychelles. Its food is mainly soft-bodied plant and animal material. Fortunately, it was never introduced to Cousine. Rodents such as the House mouse (Mus musculus), Black rat (Rattus rattus) and Brown rat (Rattus norvegicus) are a particular bane to wildlife and humans alike, by feeding on indigenous plant and animal life, and by spreading diseases. Mice occur on Aride, Mahé, Praslin and other smaller Islands. It is not known when they were first introduced but this could have been at any stage during human association with the islands. Rats were probably introduced into the Seychelles in the late 1700s, and now occur on most granitic islands except Cousin, Cousine and Aride. They have also recently been eradicated, at great cost, on
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Frégate and North islands. Rats are well known to have a major negative impact on seabirds (Jones et al. 2008), have been associated with reductions of various bird and lizard populations in the granitic islands. Their effect on the invertebrates is unknown, but is likely to have been great. Dogs and cats, being carnivores, always cause problems to wildlife. Dogs live on most inhabited islands, and used to occur on Cousine, but have not been present since 1991. Cats are commonly feral on Mahé and Praslin, feeding on tenrecs, rats, mice, lizards, snakes and birds, and have been implicated in the decline and extinction of the Seychelles magpie robin on various islands in the Seychelles. By 1985, eighty-one cats had been destroyed on Cousine, eradicating them from the island. Domestic herbivores (pigs, goats, cows and horses) greatly affect vegetation complexes, either by denuding areas while grazing or browsing, or through harvesting of fodder for them. Both pigs and cattle were kept on Cousine until 1992, and indigenous trees (such as Pisonia and figs) were cut to feed them. Alien animals generally cause problems on islands in one form or another, and where there is fierce competition for food, as there is on small islands, aliens often take a share which should be available to the indigenous species, and especially to Seychelles endemics. This is the reason why there are strict quarantine measures imposed on all humans and cargo arriving on Cousine. Continued vigilance is essential to maintain this restored paradise. A small slip could be a major ecological disaster.
COUSINE ISLAND IN THE WORLD TODAY, AND ITS FUTURE From being a largely denuded island in the 1960s, Cousine Island has been restored to a condition probably close to what it was before humans arrived. We will however, never really know for sure. Cousine nevertheless is a shining example of how indigenous nature can recover. But such recovery can only take place with insightful management, such as removal of invasive alien plants and animals in an appropriate way. Such restoration of original ecological integrity also needs a helping hand, simply because damage was done which was swift and would have been irreversible without such assistance. Reintroduction of the Seychelles magpie robin, warbler and white-eye was among one of these actions. Before restoration can take place, there must be a sound ecosystem platform on which to build. There must, for example, be no alien rats and mice. Fortunately for Cousine, these menacing creatures were, it seems, never present on the Island. If they were, then the task of restoring the island would have been even more challenging. Furthermore, there has to be constant and rigorous surveillance and quarantine the whole time so as to never let in these animals. Cousine is one of the only known tropical islands with no invasive alien mammals of any sort. With its sister island, Cousin, together they make a pair of unusual islands, being rat-free, mice-free and crazy ant-free, and under strict protection. The two islands are also close to Praslin. This is important because modern conservation genetics has shown us that certain animals require some level of outbreeding by individuals moving from one good habitat to another and meeting new mates. Occasional reintroductions and even the rare wandering from one island to another can assist metapopulation dynamics. Cousine has succeeded because of excellent communication and positive conservation action between various islands, all to the benefit of the plants and animals so urgently in need of protection. Besides genetic exchange between islands, there is also natural movement to live on a daily basis. This is seen with the Seychelles fruit bat which commutes daily and occasionally overnighting during the fruit bearing seasons to Cousine from Praslin, Cousin, Aride, La Digue and Frégate islands. And then there are the sea birds which bring in huge amounts of valuable nutrients to the Island by way of dropped food items, faeces, and their own deaths.
The important message is that while we normally think of an island as something isolated, even remote, in reality it is a crucial part of the interconnected whole. While the seabirds bring nutrients, the island on the other hand supplies safe nesting sites. The removal of all domestic animals and large patches of alien plants has shown very clearly that areas of suitable habitat for various organisms can be increased with focused management. There are now healthy populations of warblers, magpie robins, white-eyes, as well as other bird species that make Cousine exemplary in the arena of bird conservation. One of the challenging questions now, is to what extent the Island may also be able to assist in the longterm survival of other highly threatened Seychelles organisms. Other forms of encouragement management have also been necessary. Trees have been planted to boost natural succession to forest. In turn, removal of Coromandel in a crucial area has enabled the return of the Sooty tern to its grassland nesting sites. Cessation of harvesting of eggs of terns and of shearwaters has also had considerable positive effect on these birds, which have increased their numbers substantially. On Cousine, the tide of devastation has been turned, with naturally functioning and rich ecosystems having returned. Nevertheless, there still has to be vigilance to control the spread of alien plants, to keep poaching out, and to minimize disturbance to these delicate tropical food webs. The situation with turtles is still precarious. This is an issue for the world in general, and not just Cousine. Turtles have been persecuted for centuries, with the added stress today of dramatically increased beach disturbance and far more marine traffic. On Cousine, there is now a steady stream of them returning to breed. The challenge is that while they may breed well on Cousine, once they leave for the open sea, they face a whole range of threats beyond the management efforts on Cousine. The best that the Island can do is to ensure that the turtles lay eggs with minimum disturbance and that as many hatchlings as possible enter the sea to brave their new world.
Tropical Island Recovery: Cousine Island, Seychelles.1st edition. By Michael Samways, Peter Hitchins, Orty Bourquin, and Jock Henwood. Published 2010 by Blackwell Publishing Ltd.
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These, and the supporting staff, need to be maintained, which means the continual importation of certain goods and the need for the usual trappings of modern society. Besides the buildings themselves, there is a supportive infrastructure, including diesel driven generators, desalination plant and sewerage disposal facilities. Thus there is a trade off between experiencing a paradise restored and living among it. The future very much depends on how these two opposing aspects are handled. The achievements to date have been remarkable and a fair balance has been reached where both humans and wild nature thrive, but this optimism will require continual monitoring to ensure sustainability is maintained. Particular care will have to be given to adequate freshwater supplies, refuse removal, increased energy requirements, and avoidance of any diesel pollution, both on land and in the sea, which often goes hand in hand with ecotourism. The one looming feature is global climate change, which can be far-reaching and insidious. This was first seen in 1998 when western Indian Ocean sea temperatures increased (only by 2°C or so, but that was enough) and many corals and their associated communities died. This changed the character of the reef. Such events, which can have a widespread effect among organisms (such as increasing the prevalence of disease), can also reverberate along food chains. Interestingly though, the sea birds on Cousine did not seem to be affected, and this may be because the real limiting factor for them is suitable and safe nesting sites. Cousine island has addressed this key necessity, with the sea bird population responding immediately and positively to the increased area for nesting on the Island provided by the restored forest on the plain. Restoration is never static, with new findings and new challenges presenting themselves. Arguably, Cousine is a microcosm of the world we live in, and has given us pointers as to how we should manage ecosystems globally and in a way which benefits a huge array of organisms. The vision and determination of the conservators of this magnificent island have shown us that paradise can indeed be restored.
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Scientific Summary Cousine Island had, by the 1960s, been through a major regime shift. While most of the natural capital of the island survived intact, especially between the granite rocks, it was necessary to instigate a recovery programme based on knowldege of the historic vegetation condition existing in coastal areas on other, neighbouring islands. An important platform for the restoration intervention was that no rats or mice existed on the Island. This situation was an important starting point for establishing a restoration trajectory aimed at returning the full ecological integrity and, as far as we can tell, the historic ecosystem functioning. To embark on this trajectory required removal of many of the alien plants and total removal of the alien vertebrates. Poaching was also stopped. Re-establishment and canopy formation of trees on the plain led to a threshold being crossed where many alien plants were shaded out, with concurrent total population increase in many indigenous invertebrates. However, histeresis also took place with introduction of the tortoises which maintain open-canopy conditions in some low-lying areas of the island. This has been important for some sun-loving invertebrates. In other cases, intervention management has improved conditions for certain focal species. Arguably, the most significant of these has been the clearing of Coromandel, which together with cessation of poaching has enabled the return of the Sooty tern. For other focal species, particularly the endemic land birds, re-introduction has been required. This has only been possible with establishment of a more extensive forest canopy. This forest expansion has, for example, led to an increase in the Seychelles magpie robin population. Challenges nevertheless continue to surface. Among these, is the increase in the Big-headed ant population in the vicinity of accommodation on the coastal plain where the tree canopy is less dense. Scale insects in particular have been involved in a strong mutualistic relationship with ant populations, possibly also able to increase from protein resources supplied by insects attracted to lights. What we see today is a return to the likely historic condition, with some exceptions, such as the continued presence of the Indian cockroach. Interestingly, this alien insect is an important food item for the magpie robin. The situation in the sea has been very different. The regime shift from the mass bleaching event of 1998 caused a major transformation of the shallow reefs, with many species having disappeared, and some others, such as a soft coral, reaching dominant levels on the
fused coral rubble bed. Nevertheless, many coral species have reestablished, particularly on the granite boulders, which appear to be a nursery zone. However, an overarching threat is continued anthropogenic climate change, with the first indications of sea level rise. How this will affect the island as a whole is not yet known. At least for now, the declining progression towards, and 'extinction of experience,' have been reversed, with visitors now experiencing wild nature as it probably once was on many small tropical islands, with a dense carpet of vegetation and the clamour of nesting sea birds bringing nutrients into an intrinsically nutrient-poor system. These populations can only be maintained with continued removal of alien plants and maintenance of a strict quarantine programme. Cousine Island today is a microcosm of ecological restoration for future generations to appreciate.
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LIST OF SPECIES RECORDED ON AND AROUND COUSINE Endemic means that it occurs in the Seychelles and nowhere else Indigenous means that it occurs naturally in the Seychelles and elsewhere as well Alien means that it is introduced into the Seychelles from elsewhere, either accidentally or deliberately Introduced means that is has been deliberately introduced onto Cousine from elsewhere in the Seychelles, although it may not necessarily have occurred naturally on Cousine Re-introduced means that it once occurred on Cousine but has since died out, but now brought back onto the Island Common names in blue are the Creole names Note This checklist is far from complete, as many species still remain unidentified and/or are new to science. Many representatives of families that are not listed here have been collected (especially invertebrates, both terrestrial, e.g. flies, and marine, e.g. sponges). These are listed at the end of this checklist. This list therefore is the state of knowledge of the biodiversity of the island at the genetic and/or species level. The unidentified species that are mentioned in this checklist are among the most conspicuous members of the fauna, many of which have been photographed. COMMON NAME SCIENTIF IC NAME KINGDOM: PROTOCTISTA (PR OTISTS)
NOTE S
Phylu m: Ch lorophyta (Gre en algae) Sea le ttuce
Ulv a sp.
Indigenous
Antenna-weed
Chaetomorpha sp.?
Indigenous
Cladophora
Cladophoropsis sp.?
Indigenous
Chlorodesm us
Chlorodesmis sp.
Indigenous
Tur ke y tail A
Padina boyana ?
Indigenous
Tur ke y tail B
Padina sp.
Indigenous
Sa rgassum A
Sargassum c ristaefolium
Indigenous
Phylu m: Ph aeophyta (B rown algae)
Sa rgassum B
Sargassum binderi ?
Indigenous
Sa rgassum C
Sargassum sp.
Indigenous
Tur bin weed
Turbinaria sp.
Indigenous
Dictyota
Dic tyota sp.
Indigenous
Dictyopteris
Dic tyopteris sp. ?
Indigenous
Phylu m: Rh odoph yta (Red algae ) Wine-weed
Rhodydenia sp.?
Indigenous
Aga r-weed
Gracilaria sp.?
Indigenous
Fine-fork cor alline
Jania adhaerans?
Indigenous
Nodula r coralline
Amphiora sp.?
Indigenous
Fea ther weed
Asparagopsis tax iformis
Indigenous
Swamp f ern, Fouzer lanmar
Acrostichum aureum
Indigenous
Isla nd f ern, Fouze r taba
Nephrolepis biserrata
Indigenous
Ceratopsis cornuta
Alien/era dicated
Ba lfour's panda nus, Vakwa bor-d-m er
Pandanus balfourii
Introduc ed
Use ful pandanus, Vakwa
Pandanus utilis
Alien/era dicated
Ba mboo, Banbou
Bambusa vulgaris
Alien/in proc ess of being e radicated
Coast brachiaria
Brachiaria subquadripara
Indigenous
Lemon grass, Pti sitronel
Cymbopogon citratus
Alien/ cultivated in prescribed a re; used in cooking
Couch grass, Syendan
Cynodon dac tylon
Alien/natura lly controlled by development of
Comb grass, Lerb bourik M any fingers
Dac tyloctenium cte noides Digitaria ciliaris
KINGDOM: PLANTAE (PL ANTS) Phylu m: Fe licinop hyta (Fer ns) Family: Polypodiaceae
Family: Pa rkeriacea e Water fer n, Kreson lanmar Phylu m: An giospe rmophyta (S eed plants) Class: Monocotyledoneae (Monocots) Family: Pandanacea e (Sc rew-pines)
Family: Gra minae (Bamboos and grasses)
restored forest
182
Indigenous Alien/non-inva sive
Couch grass, Syendan
Cynodon dactylon
Alien/naturally controlled by development of restored forest
Comb grass, Lerb bourik Many fingers
Dactyloctenium ctenoides
Indigenous
Digitaria ciliaris
Alien/non-invasive
Delicate finger grass Goose grass, Pat-depoul
Digitaria radicosa Eleusine indica
Alien/non-invasive
Seychelles enteropogon, Gazon
Enteropogon seychellensis
Indigenous
Love grass Short spike lepturus Long spike lepturus
Eragrostis tenella Lepturus radicans Lepturus repens
Alien/non-invasive
Forest panicum, Lerb lasenn
Panicum brevifolium
Indigenous
Guinea grass, Fatak
Panicum maximum
Swamp grass
Paspalidium geminatum
Alien/invasive; being eradicated/ introduced prior to 1946 for manufacture of house brooms Indigenous
T-grass Fox tail, Lerb
Paspalum conjugatum Pennisetum polystachyon
Alien/non-invasive
matant Coast grass Broad-leaf steno,
Sporobolus virginicus Stenotaphrum dimidiatum
Indigenous Indigenous
Lerb koko Fine steno, Lerb lasenn
Stenotaphrum micranthum
Family: Cyperaceae (Sedges) Compressed sedge Conglomerate sedge Spiky sedge
Cyperus compressus Cyperus conglomeratus Cyperus rotundus
Indigenous Indigenous
Round-headed sedge Green-headed sedge
Fimbristylis cymosa Kyllinga polyphylla
Indigenous Indigenous
White-headed sedge Common sedge Swamp sedge
Mariscus dubius Mariscus ligularis Mariscus pennatus
Indigenous
Feathery sedge Family:
Pycreus polystachyos
Orchidaceae (Orchids) Vanilla, la vaniy
Vanilla planifolia
Family: Palmae (Palms) Coconut palm, Pye
Cocos nucifera
koko Family: Araceae (Arums) Silver queen
Indigenous
Alien/eradicated
Natural colonizer but also introduced/invasive/ being eradicated except along the beach
Aglaonema commutatum
Alien/eradicated
183
Yam, Tannia
Alocasia mac rorrhiza
Alien/eradicated
Commelina
Alien/era dicated
Family: Com melinacea e (Spider worts) Wandering jew, Lerb koson
benghalensis Commelina diffusa
Recorded in 1972, but no longer present
M other -in-law's tongue
Sansevie ria trifasciata
Alien/era dicated
M auritius he mp, Gro agav
Furcrae a foetida
Alien/rec orded in 1972, but no longer present
Sisal, Lalwa
Agave sisalana
Alien/era dicated
St Joseph's lily, Lis sen zozef
Crinum zeylanicum
Alien/era dicated
Spider lily, Lis bor-d- mer
Hymenocallis littoralis
Alien/not inva sive/retained for aesthetic reasons
Musa sapientum
Alien/not inva sive/cultivated fruit tree in prescribed area
Ery throxylum
Endemic/ introduced onto Cousine as part of the genera l
seychellarum
conservation plan for the species
Wandering jew Family: Liliacea e (Lilies)
Family: Am aryllidacea e (Amaryllis family)
Family: Musac eae (B ana na fam ily) Banana, Banann Class: Dicotyle don eae (Dicots) Family: Er ythroxylaceae (C ocoas) Se ychelles cocoa Family: Sapindaceae (Soapberries) Perville’s soa pberry, Bwa kafoul
Allophylus pervillei
Indigenous/ introduced as a favoured plant by the Seyc helles white-eye
Family: Leguminosae (Legum es) Canoe intsia , Gayac
Intsia bijuga
Indigenous/ introduce d
Yellow necklace pod, B wa
Sophora tomentosa
Indigenous/pantropical/ arrived naturally on dune crest in 2007
Soursop, Korosol
Annona muricata
Alien/cultiva ted fruit tree in prescribed area
Custa rd apple, Zat
Annona squamosa
Alien/cultiva ted fruit tree in prescribed area
Persea americana
Alien/cultiva ted fruit tree in prescribed area
White hernandia, Bois Blanc,
Hernandia
Indigenous to Seychelles/ reintroduced to Cousine
Bwa blan
nymphaeifolia
chapele t Family: Annonacea e (Custar d apples)
Family: Laurac eae (Laurels) Avocado, Zavoka Family: Her nandiac eae (Hernandias)
Family: Moraceae (Fig a nd mulber ry family) Br eadfruit, Friya pen
Artocarpus altilis
Alien/cultiva ted fruit tree in prescribed area
Large-leaf fig, Lafous gran fey
Ficus lutea
Indigenous/ propa gated on Cousine
Sm all-leaf fig, Lafous pti fey
Ficus reflexa ssp.
Indigenous/propagated on C ousine
seychellensis
184
Family: Casua rinaceae (Casuarinas) Ca suarina, Sed
Casuarina equise tifolia
Alien; planted 1946 and 1952/e radicated
Family: Nyctaginaceae (Four- o’clock fam ily) Pisonia , M apou
Pisonia grandis
Little stic ky seed, Patat kovin
Boe rhavia repens
Indigenous
Bouga invillea, Vilea
Bougainvillea glabra
Alien/era dicated
Opuntia vulgaris
Alien/era dicated
Spikeweed, Lerb ser zan
Ac hyranthe s aspera
Alien/ reduced but still present
Pig weed, B red pa ryater
Amaranthus dubius
Alien/almost eradicated
Sessile alternanthera, Bred anbala z
Alte rnanthera sessilis
Alien/almost eradicated
Portulaca oleracea
Alien/ used as a salad item on Cousine
Calophylum
Indigenous/propoga ted on Cousine
Indigenous/propoga ted on Cousine /high conservation priority
Family: Cactaceae (Cacti) Ca ctus, prickly pear, raket pikan Family: Am aranthacea e (Amaranths)
Family: Por tula caceae (Purslanes) Fleshy portulaca, Pourpye Family: Guttiferae (Ga rcinias) Ale xandria n Laurel, Takam aka
inophyllum Family: Tiliacea e (Lindens) Rhombic triumfetta , Lerb panyen
Triumfetta
Alien/era dicated
rhomboidea Family: Ster culiaceae (Sterculias) Heritiera littoralis
Indigenous/reintroduced on Cousine
Indian abutilon, Mov di peyi
Abutilon indicum
Alien/being era dicated
Sea hibiscus
Hibiscus tiliaceus
Indigenous/propagated on C ousine
Rosewood, Bwa-d-roz
Thespesia populnea
Indigenous/propagated on C ousine
Cotton, Koton
Gossypium hirsutum
Alien/era dicated
Narrow lea f sida, Lerb dir Family: Lec ythidaceae (Barr ingtonias)
Sida acuta
Alien/era dicated
Fish-kill tree, Bonnen kare, Bor-d-mer
Barringtonia asiatic a
Indigenous to S eychelles/reintroduced to Cousine
Turnera angustifolia
Alien/being era dicated
Wild grenadilla, Bonbon plim
Passiflora foetida
Alien/being era dicated
Grenadilla , Pa ssion fruit, fri-d- lapasyon
Passiflora edulis
Alien/era dicated
Carica papaya
Alien/requires continual control outside cultivated area
Cleome v iscosa
Alien/era dicated
Senna occidentalis
Alien/almost eradicated
Sirris tr ee, B wa nwar
Albizia lebbe ck
Alien/era dicated
Hedge acacia, Ka si
Leucaena
Alien/era dicated
Looking-glass tr ee, B wa- d-tab Family: Malvac eae (M allows)
Family: Turneracea e (Turnera s) Yellow alder, Koket Family: Passiflorac eae (Pa ssionflowers)
Family: Caricaceae (Caricas) Pa paya, Pawpaw, Papay Family: Capparidac eae (C apers) Sticky cleome, Pisa r lisyen Fam ily: C aesalpiniacea e (Sennas) Stink weed, Kaspyant Family: Mimosacea e (Mimosas)
leucocephala
185
Family: Papilionaceae (Sesbania s) Cr abs eyes, Lalya nn r eglis
Abrus prec atorius ssp
Alien/er adicated
africanus Sesbania, Kasi m aron
Sesbania seric ea
Alien/er adicated
Wild bean
C anavalia cathartica
Indigenous/controlled at seabird nesting sites (from too heavily infesting the site s)
Family: Myr tac eae (M yrtle s) Psidium guajava
Alien/er adicated
T erminalia catappa
Indigenous/propa gated on Cousine
Xime nia americana
Indigenous?
Phyllanthus pervilleanus
Indigenous
Longfruit phyllanthus
Phyllanthus tenellus
Alien/r are on Cousine
Short-f ruit phyllanthus,
Phyllanthus amarus
Alien/not invasive/scheduled for eradication
Phyllanthus acidus
Alien/scheduled for era dication
Indian ac alypha , Lerb sat
Acalypha indica
Fire-leaf euphor bia, Tangen
Euphorbia py rifolia
Alien/r educed but not yet er adicated Indigenous
Hairy euphorbia, Za n rober
Euphorbia hirta
Alien/ invasive
Prostra te euphor bia, Trenas
Euphorbia prostrata
Alien/inva sive
Slipper flower , B wa malga s
Pedilanthus tithymaloides
Alien/er adicated
Codia eum , C roton
C odiaeum variegatum
Alien/er adicated
Ca stor oil, Tanta n
Ricinus communis
Alien/er adicated
Mangife ra indica
Alien/not invasive/cultivated in prescribed are a
Xylocarpus moluccensis
Indigenous/reintroduc ed to Cousine
C lausena excavata
Alien/not invasive/ cultivated in prescribed area
Lim e, Limon
C itrus aurantifolia
Alien/not invasive/cultivated in prescribed are a
Seville orange, Zoranz
C itrus aurantium
Alien/not invasive/cultivated in prescribed are a
Kum quat, Bigard
C itrus aurantium ssp.
Alien/not invasive/cultivated in prescribed are a
Lemon, Lim on
C itrus limon
Alien/not invasive/cultivated in prescribed are a
Mimusops seychellarum
Endem ic
Gua va, Gouyav Family: Com bretac eae (C ombretums) Pa cific a lmond, Badam yen Family: Olacac eae (Olaxes) Sour plum Family: Euphorbiac eae (Spurges) Se ychelles phylla nthus, Bwa kastik
Keraneli blan Otahe ite gooseber ry, Bilenbel
Family: Anacar diaceae (C ashews) M ango, M anng Family: Meliac eae (M ahoganies) Puzzle-nut, Mangliye ponm Family: Rutacea e (Rues) Topflower cla usena, Karipile
anmer bigaradier va r mitis Family: Sapotac eae (S apote fam ily) Se ychelles m imusops
186
Family: Apocynace ae (Dogbanes) Ochrosia, B wa sousouri
Ochrosia
Indigenous/reintroduced to C ousine
oppositifolia M ada gascar periwinkle, Roz
Catharanthus
anmer
roseus
Bwa dile
Tabernaemontana
Alien/substantially reduced through developing tree c anopy Indigenous/re-introduced for the Seychelles white-eye
coffeoides Family: Solanaceae (Nightsha de s) Chilli, Piman m arten
Capsicum
Alien/not invasive/cultivated in prescribed a rea
frutesc ens Poison apple, Fler pwa zon
Datura metel
Alien/eradic ated
Nightshade, B red marten
Solanum
Alien/eradic ated
americanum Nicotiana tabacum
Alien/eradic ated
Large-leaf m orning glory, Patatran bla n
Ipomoea macrantha
Indigenous
Bea ch morning glory, Patatran
Ipomoea
Indigenous
rouz
pescaprae
Five-lea f morning glory
Ipomoea venosa
Indigenous
Coast cordia, Porse
Cordia subcordata
Indigenous/propagated on Cousine
Tree heliotrope, Bwa Taba
Argusia argenta
Indigenous to Seyc he lles/reintroduc ed to C ousine but
(Tournefortia
introduc tion fa iled
Tobacc o, Taba Family: Convolvula ceae (M orning glories)
Family: Boraginace ae (B orages)
argentea) Family: Scrophular iace ae (Figworts) Red striga, Lerb dife
Striga asiatica
P ossibly indigenous/only arrived on Cousine in May 1995 when granite wa s brought over from Praslin f or construction pur poses
Family: Verbenaceae (Ver benas) Jamaican vervaine, Zepi ble
Stachytarpheta
Alien/be ing eradic ated
jamaic ensis Vervaine Ocimum, B asilik Leonotis, M ont o syel
Phylla nodiflora Ocimum sp. Le onotis nepetifolia
Alien/eradic ated Alien/cultivated in prescribe d area Alien/eradic ated
Family: Labiatae (M int family) Pre mna
Indigenous/introduc ed to C ousine as part of the Seychelles
obtusifolia
white-eye re introduction project
Scaevola sericea
Indigenous/propagated on Cousine
Indian m ulberry, Bwa torti
Morinda citrifolia
Indigenous/propagated on Cousine
Gue ttarda, Bwa kasan
Guettarda
Indigenous/reintroduced to C osuine
False elder, B wa siro
Family: Goodeniac eae (Goodenia s) Half-flower, Vouloutye Family: Rubiac eae (M adders)
spe ciosa
187
Corymbose heydoti, Lerb
Hey dotis
tourtrel
corymbosa
Wright's gardenia, Bwa
Rothmannia
sitron
annae
Coffee, Kafe, Bwa dir
Coffea arabica
Alien/era dicated
Canthium
Indigenous but introduced to Cousine as a stipulation for introduction of
bibracteatum
Seychelles white-eye
Vernonia
Alien/lim ited distribution in disturbed areas
Alien/non-inva sive Indigenous/reintroduced to Cousine/high conservation status
rouz Two-bract c anthium Family: Composita e (C omposites) Vernonia, Gerivit
cinerea Family: Moringacea e (M oringa s) Hor se radish tree, Bred
Moringa
mouroung
oleifera
Alien/cultiva ted in presc ribed are a
Family: Simarouba ceae (Quassias) Suriana, B wa matlo, Bwa
Suriana
Indigenous/arrived na turally in 2000 on C ousine by beaching seed, but by
damann, B wa se v
maritima
2007, it ha d disa ppeared owing to erosion of the dune slope/was recorded on Cousine in 1972
Family: Ona gra ceae (Evening primroses) 8-valve ludwigia
Ludwigia
Alien/era dicated
octovalvis Family: Oxa lida ceae (Oxalis familay) Ave rrhoa, Bile nbi
Ave rrhoa bilimbi
KINGDOM: FUNGI Or der: Agaricales Phylu m: Basidiomycota Japanese um brella
Coprinus sp.?
Or der: Aphyllophiorales Orange bracket
Py cnoporus
Honeycomb bracket
He xagona sp.?
sp.?
188
Alien/era dicated
Not good quality KINGDOM: ANIMALIA (ANIMALS ) Phylu m:Porif era (Sponges) Class: Calcarea (B ritt lesponges) Veined sponge
Echinochalina sp.
Phylu m: Cn idaria (Corals, jellyfish, sea anemone s) Class: Hydrozoa (Hydroids) Family: Milleporidae (Fire cora ls) Fire c oral
Millepora sp.
Class: Anthozoa (Sea anenome s and corals) Or der: Alcyonacea ( Sof t corals) Family: Tubiporida e Organ- pipe coral
Tubipora music a
Survived the great bleaching event very well, with severa l colonies pre sent on the fused coral rubble
Family: Alc yoniida e (Soft corals) M ushroom leather coral
Sarcophyton sp.
Knobbly leather coral
Cladiella australis
Or der: Actiniaria (Regular anenome s) Family: Stic hodactylidae M agnificent sea anenome
He teracris
Skunk anemone fish associates with this species; this anemone species
magnifica
was lost in the grea t bleaching event of 1998 and had not reappe ared by 2008
M ertens’ sea a nenome
Stichodactyla
Seyc helles anemone fish associates with this species; this anemone
me rtensii
species was lost in the great bleac hing event of 1998 and had not reappe ared by 2008
Or der: Zoanth idea ( Zoanth ids) Family: Zoa nthidae (Zoa nthids) Light gre en zoa nthid
Zoanthus sp. 1
?
Olive zoanthid
Zoanthus sp. 2
?
Or der: Actiniar ia (S ea an emones) Family: Hor manthiidae Hermit crab anem one
Ve rillactis paguri
189
Order: Scleractinia (Hard corals) Family: Pocilloporidae (Knobhorns) Knobhorn coral
Pocillopora damicornis
Knobhorn coral
Pocillopora eydouxi Pocillopora
Flat-branch coral
verrucosa Stylophora
Knobhorn coral
Very common in high wave energy areas
pistillata Family: Acroporidae (Staghorns) Delicate staghorn coral
Acropora austera
Plate coral
Acropora clathrata
Eliminated from the fringing reef by the great bleaching event and currently re-establishing on the granite boulders
Dwarf staghorn coral
Eliminated from the fringing reef by the great bleaching event
Staghorn coral
Acropora gemmifera Acropora formosa
Finger staghorn coral
Acropora humilis
Robust staghorn coral
Acropora robusta
Noble coral
Acropora nubulis
Many-eyed coral Warty coral
Astreopora myriophthalma Montipora
Warty coral
monasteriata Montipora digitata
Family: Poritidae (Porous corals) Porous coral Porous coral
Porites ?lutea Porites solida
Large colonies survived the great bleaching event very well Large colonies survived the great bleaching event very well
Peacock coral
Pavona clavus
Very resistant to the great bleaching event, with a very large colony surviving and thriving after 1998
Peacock coral
Pavona varians
Plate coral
Leptoseris mycetoseroides
Large colonies eliminated from fringing reef by the great bleaching event Large colonies eliminated from the fringing reef by the great bleaching event Eliminated from the fringing reef by the great bleaching event Elimated from the fringing reef by the great bleaching event
Family: Agariciidae (Peacock corals)
Family: Fungiidae (Mushroom corals) Mushroom coral Mushroom coral Family: Oculindae (Oculines) Velvet coral
Fungia scutaria. Fungia fungites Galaxia fascicularis
Family: Mussidae (Brain corals) Brain coral
190
Symphyllia cf recta
Brain coral
Lobophyllia hemprichii
Brain coral
Lobophyllia corymbosa Acanthastrea
Spiny honeycomb coral
echinata Family: Favidae (Honeycomb corals) False honeycomb coral False honeycomb coral
Favia matthai Favia pallida
False honeycomb coral ‘Massive honeycomb coral’
Favia speciosa Diploastrea heliopora
Knobbly coral
Echinopora gemmacea
Lamellate coral Honeycomb coral
Echinopora lamellosa Favites halicora
Honeycomb coral Little knobbly coral
Favites pentagona Cyphastrea
Little knobbly coral
chalcidicum Cyphastrea micropthalma
Eyed honeycomb coral
A large colony on the front of the fringing reef and estimated to be over 1000 years old was eliminated by the great bleaching event Eliminated from fringing reef by the great bleaching event
Leptastrea transversa
Family: Siderastreidae Digit coral
Psammocora digitata
Fused coral
Psammocora contigua Coscinaraea sp.
Sieve coral Order: Antipatharia (Black corals) Spiral black coral Branching black coral
Cirrhipathes sp. Antipathes sp.
Phylum: Mollusca (Snails, slugs, chitons, octopi, and squids) Class: Gastropoda (Gastropod molluscs) Subclass: Prosobranchia (Snails) Family: Patellidae (Limpets) Banded limpet Rayed limpet False limpet Family: Trochidae (Top
Cellana livescens Patella pica Siphonaria sp.
shells) Radiate top-shell Mauritian top shell
Trochus radiatus Tectus mauritianus
Virgo top shell Floret top shell
Tectus virgatus Clanculus flosculus
Family: Turbinidae (Turbans) Silver mouthed turban
Turbo agryrostomus
191
192
Brown turban
Turbo bruneus
Sword turban Family: Neritidae (Nerites) Blotched nerite
Turbo saxosus Nerita albicilla
Toothed nerite Smooth nerite Textile nerite
Nerita plicata Nerita polita Nerita textilis
Grey nerite Tongue nerite
Nerita undata Neritopsis radula
Family: Littorinidae (Periwinkles) Striped periwinkle Family: Modulidae (Modulus
Littoraria glabrata
shells) Squat modulus
Modulus tectum
Family: Cerithiidae (Ceriths) Prickly cerith Wasp cerith
Cerithium echinatum Cerithium sp.
Marginated cerith Family: Melanellidae (Melanellas)
Cerithium atromarginatum
Cuming’s melanella Family: Strombidae (Conches) Variable stromb
Melanella cumingii
Arthritic spider conch Common spider conch Giant spider conch
Lambis chiragra arthritica Lambis lambis Lambis truncate
Orange spider conch Family: Naticidae (Moon shells)
Lambis crocata
Comma moon shell Family: Cypraeidae (Cowries) Gold ringer
Natica gualteriana
Arabian cowrie Eyed cowrie
Cypraea arabica Cypraea argus
Little ass cowrie Serpent's-head cowrie Carnelian cowrie
Cypraea asellus Cypraea caputserpentis Cypraea carneola
Dawn cowrie Globular cowrie
Cypraea diluculum Cypraea globulus
Honey cowrie Netted cowrie Isabella cowrie
Cypraea helvola Cypraea histrio Cypraea isabella
Money cowrie Warty cowrie Mole cowrie
Cypraea moneta Cypraea nucleus Cypraea talpa
Tiger cowrie Family: Cassidae (Helmet shells)
Cypraea tigris
Common bonnet Family: Tonnidae (Tun shells) Partridge tun
Casmaria erinaceus
Strombus mutabilis
Cypraea annulus
Tonna perdix
Family: Ranellidae (Tritons) Golden triton
Cymatium nicobarium
Lacuna triton Old woman
Gyrineum lacunatum Distorsio anus
Family: Janthinidae (Violet shells) Violet snail Family: Muricidae (Rock shells)
Janthina janthina
Rough castor bean Castor-bean shell Porcupine castor bean
Drupa morum Drupa ricina Drupa rubusidaeus
Spiked morula Granulated morula
Morula aspera Morula granulata
Lumpy morula Francolin rock shell Branched murex
Morula uva Nassa francolina Chicoreus lambis
Fenestrate cronia Spotted rock shell
Cronia fenestrata Maculotriton serriale
Conicate morula Striped morula Intermediate thais
Habromorula biconica Habromorula striata Thais intermedia
Salmon-lipped whelk Family: Bursidae (Frog
Thais purpurapanama
shells) Granular frog shell Rose frog shell
Bursa granularis Bursa rosa
Lamp shell Family: Columbellidae (Dove shells)
Tutufa bubo
Turtle dove shell Variable dove shell
Columbella turturina Columbella varians
Tortoise pyrene Family: Buccinidae (Whelks)
Pyrene testudinaria
Waved whelk Family: Nassaridae (Dog
Cantharus undosus
whelks) White dog whelk Gaudy dog whelk Family: Turbinellidae (Vase shells) Common vase shell Family: Fasciolaridae (Tulip shells) Threaded band shell Ridged tulip Little nassa tulip Family: Mitridae (Mitre shells) Lettered mitre Family: Conidae (Cone
Nassarius albescens gemmuliferus Nassarius gaudiosus
Vasum turbinellus
Fasciolaria filamentosa Latirus polygonus Peristernia nassatula
Mitra litterata
shells) Court cone
Conus aulicus
Canon cone
Conus canonicus
193
Worm cone
Conus c haldeus
Cr owne d cone
Conus c oronatus
Black and white cone
Conus e braeus
Flavid c one
Conus flavidus
Geogra pher cone
Conus geographus
Imperial cone
Conus impe rialis
Leopar d cone
Conus leopardus
Lithograph cone
Conus liloglyphus
Ashen cone
Conus lividus
Soldier c one
Conus mile s
Little spotted cone
Conus nussatella
Ra t cone
Conus rattus
Tulip cone
Conus tulipa
Family: Terebridae (Auger shells) Spotted auge r
Te rebra maculata
Sub class: Opisthob ran chia (Sea Slugs) Or der: Cep halaspidae ( Bubble shells) True bubble
Bulla ampulla
Or der: Nu dibranc hia (Nud ibranch s) Spanish dancer
Hexabranchus sanguineus
Or der: Anaspidea (Sea hares) Ringed sea ha re
Aplysia dactylomela
Sub class: Pulmonata (Air-b reathing snails and slugs) Family: Achatinidae (Achatinas) Gia nt African snail, Gro
Achatina fulica
kourpa
a pparently died out as a result of drought
Family: Subulinida e (Awl snails) Little spiral-shell
Subulina oc tona
Family: Onc hididae (Onchidellas) Isla nd onchidella
Onchidella sp.?
Family: Siphonaridae (False lim pets) Little false limpet
Siphonaria sp.
Family: Aur iculidae (Earshells) Pa le e arshell
Melampus lividus
Class: Polyplacophora (Chiton s) Family: Chitonidae (C hitons) Black-scaled chiton
Chiton sp.
Hairy chiton
Acanthopleura gemmata
Class: Cep halopoda (Squids and octopi) Or der: T euthoidea (Squ ids) Family: Loliginidae (Squids) Indian ocean squid
194
An edible a lien species that was once present on Cousine but
Loligo duvancelli
Family: Octopodida e (Octopi) Spotted octopus
Octopus sp.
Class: B ivalvia (B ivalves) Family: Arcida e (Ark shells) Foliate a rk shell
Barbatia foliata
Family: Mytilidae (Mussels) Ear mussel
Modiolus auric ulatus
Family: Pteriidae (Pearl oysters) Imbricate pearl oyster
Pinctada imbric ata
Black pearl oyster
Pinctada nigra
Family: Isognom onida e (Tree oysters) Nut tooth pearl
Isognomon nuc leus
Family: Ostreidae (Oysters) Hooded oyste r
Saccostre a cucullata
Family: Pec tinidae (S callops) Coral scallop Family: Spondylida e (Thorny
C ryptopecten ?nux
oysters) Thorn oyster
Spondylus sp.
Family: Luc inidae (Lucinids)
C odak ia tigerina
Tiger codakia Family: Car ditidae (Fa lse cockle s) Rec tangular giant clam
C ardita variegate
Family: Tridacnidae (Giant clam s) Fluted giant c lam
Tridacna squamosa
Elonga te giant cla m
Tridacna maxima
S urvived the great blea ching event very well
Family: Veneridae (Venus clams) Tor euria venus
Venus toreuria
Family: Teredinidae ( Shipworm) Ship worm
Bank ia sp.
Phylu m: An nelida (W or ms) Class: Polyc hae ta (Brist leworms) Family: Eunicida e Pa lolo worm
Eunice sp.?
Inhabits crevic es on coral reef
M edusa tangleworm
Loimia medusa ?
B uried in muddy sand
Pontoscolex corethrurus
Introduced
Eudrilus eugeniae
Introduced
Class: Oligochaeta (Earthworms) Family: Glossocolecida e Br oom ea rthworm Family: Endrilidae Tropical earthworm Family: Octochaetidae Log e arthworm
Dichogaster affinis
Phylu m: Ar thropoda (Arthropods) Sub phylu m: Myriapoda (Milliped es and centiped es)
195
Class: Symp hyla (Symphyla) Symphyla
Symphyla sp.
Class: Diplopoda (Millipede s) Family: Spirostrepsida e Se ychelles giant
Seychelleptus
Indigenous/importa nt for soil formation/ has benefited from
millipede, Gro milpat
seychellarum
r estor ation of plain forest
Stripe d-headed
Identity uncertain
Indigenous/has benefited fr om restoration of pla in forest and com mon
millipede
under felled Coconut palm and C asuarina logs; this unidentified species is m entioned here in view of its conspicuousne ss in the r estor ation pr oject
Family: Spirobolellidae Nares’millipede
Trigoniulus naresi
Nether la nd m illipede
Pseudospirobolellus avernus
Family: Pac hybolidae Dacty lobolus
Endemic, restricted to Western India n Ocea n atolls, and, strangely,
biv irgatus
only C ousine a mong the gra nitics
Orthomorpha gracilis
Indigenous/ has benefited from restora tion of plain forest
Red-legged c entipede,
Scolopendra
Indigenous/has benefited fr om restoration of pla in forest/has a painful
Sa npye
subspinipes
bite
Blue-le gged centipede
Otostigmus cf
Long-stripe millipede Family: Pa radoxosomatidae Keeled millipede Class: Chilopoda (Centipedes) Or der: Scolopendr omorpha Family: Sc olopendridae
orientalis Little wrinkled
Otostigmus rugulosus
millipede M embrane centipede
Cryptops philammus
Indigenous/ has benefited from restora tion of plain forest
Mecistocephalus
Indigenous/ has benefited from restora tion of plain forest
Or der: G eophilomorp ha Family: Geophilidae Isla nd litter c entipede
insularis VanMot’s
Mecistocephalus cf
littercentipede
vanmoti
Slender litter centipede
Nesoge ophilus
Endemic
leptochilus Or der: L it hobiomorph a Family: Lithobiobidae Stone centipede
Lamycetes sp. cf
Indigenous/ has benefited from restora tion of plain forest
albipes Class: Insec ta (Insects) Or der: O donat a (Dr agonflies and damse lf lies) Sub or der : Zygoptera (Damself lies) Family: Coenagrionidae (Pond damsels) Comm on citril
Ceriagron glabrum
Indigenous/ appe ared from neighbouring islands with construction of tortoise ponds but ha s since disappea red with growth of plain fore st
196
Suborder : Anisoptera (Dragonflies) Family: Aeshnidae (Hawkers) Vagrant emporer Amberwing emporer
Anax ephippiger Anax guttatus
Indigenous/vagrant Indigenous/vagrant
Family: Libellulidae (Skimmers) Blue percher
Diplacodes trivialis
Indigenous/appeared with construction of tortoise ponds but has since disappeared with growth of plain forest Indigenous
Twister
Orthetrum stemmale wrightii Tholymis tillarga
Pantala Continental glider
Pantala flavescens Tramea limbata
Seychelles skimmer
Indigenous/ arrives periodically from neighbouring islands to inhabit tortoise ponds but now rare with growth of plain forest Indigenous/migrant/ larva occurs in bird baths Indigenous/migrant
Order: Orthoptera (Bush crickets, crickets and grasshoppers) Family: Tettigoniidae (Bush crickets) Common cone-head Common ruspolia Family : Gryllidae (Crickets) Entreating cricket Darting green tree cricket
Conocephalus sp. Ruspolia differens
Indigenous/common among grass and Coromandel Indigenous/very loud, buzzing song/ in long grass
Gryllodes supplicans Pteronemobius sp. cf tapobranensis
Alluaud’s spider cricket Phalangacris alluaudi Family: Mogoplistidae (Short-winged crickets) Short-winged cricket Urnebius sp.
Endemic; lives in rock overhangs
Family: Acrididae (Grasshoppers) Zanzibar grasshopper
Jasomenia sansibara
Indigenous/ has declined with growth of plain forest but inhabits sunlit, open areas grazed by tortoises
Order: Dermaptera (Earwigs) Family: Carcinophoridae Ringlegged earwig
Euborellia annulipes
Alien
Euborellia stali
Alien
Labia minor
Alen
Gonolabris electra
Alien
Periplaneta americana
Alien/confined to dwellings/eradicated whenever encountered
Blattella germanica
Alien/confined to Pavilion
Pycnoscelus indicus
Alien/important food item for Seychelles magpie robin
Stal's earwig Family: Labiidae European earwig Bright earwig Order: Blattodea (Cockroaches) Family: Blattidae American cockroach German cockroach Family: Blaberidae Indian cockroach Order: Isoptera (Termites) Family: Termitidae
197
Black snouted term ite
Nasutitermes nigritus
Sloping-fa ce termite
Arrhinotermes calanifrons
Sc ott’ s termite
Calotermes scotti
Introduc ed/ c omm on in association with Coc onut palm on hillsides Introduc ed/has be nefited from inc reased forest cover Introduc ed/ has benefited from increased forest cover
Or der: H emipte ra (Plantbugs, cicadas, leaf hoppers, aphids, scale inse cts) Sub or der: Heteroptera (True bugs) Family: Reduviidae (Assasin bugs) Assassin bug A
Onc oce phalus sp.
Family: Anthoc oridae (M inute pirate bugs) Typical minute pirate- bug
Ostorodiasoide s typic us
Endemic
Sc ott’ s minute pirate-bug
Lasiochilus scotti
Endemic
Felisac us auritulus
Endemic
Family: Mirida e (Mirids) Sm all-eared mir id Family: Lygaeidae (S eedbugs) Seedbug A Family: Cydnidae (Burrower bugs)
Nysius sp.
Black burrower bug
Mac roscyte s sp.
Family: Pentatomidae (Shield bugs) Green shield bug
Nezara viridula
Shield bug A
Bathycoelia sp.
Fern shield bug
Chilocoristoides feliciatus
Alien/pest of ve getables
Sub or der: Hom optera (P lanthoppers, sca le insects, aphids and allies) Family: Cicadellida e (Leafhoppers) Silhouette leafhopper
Paralimnus silhoettensis
Br owed leafhopper
Exitianus frontalis
Dwa rf leafhopper
Exitianus nanus
Endemic
Long leafhopper
Aconeurella prolixa
Endemic
White-girdled lea fhopper
Orosius albic inctus
Endemic
Rec ilia le afhopper
Recilia sp.
Two-spot leafhopper
Nehela bimac ulic ollis (+ 2 other
Alien
Nehela spp.) Green leafhopper
Paganalia viresce ns
Endemic
Incomplete leafhopper
Jakellrella ineffectus
Endemic
Se ychelles leafhopper
Scaphoideus seyc hellensis
Endemic
Ptye lus mahei
Endemic
Family: Cer copidae (Spittlebugs and froghopper s) Se ychelles spittlebug
Family: Margarodidae (C ottony cushion scale insects) Se ychelles cottony cushion scale
Icerya seychellarum
Despite the nam e, probably alien/ can form hea vy infestations on severa l species of tree a nd which are aggravated by the introduc ed Big-headed ant/
Comm on cottony cushion scale
198
Ice rya purchasi
important food item for Seychelles white-eye Alien/ on citr us
Family: Pseudococ cidae (Mealybugs)
.
M ealybug A
Dysmicocc us sp
M utualistic with B ig-he ade d ant
M ealybug B
Planococcus sp.
M utualistic with B ig-he ade d ant
Or der: T hysanoptera (T hrips) Family: Thr ipidae Anoma lous thrips
Brachy urothrips
Comm on thrips
Thrips sp.
anomalus Or der: Neu rop tera (Lacewings, An tlions) Family: Myrmeleontida e (True antlions) My rmeleon obscurus
Indigenous
Hydrosternum beetle
Hydrosternum sp.
Indigenous
Water-scavenger beetle
Coe lostoma cf
Yellow banded antlion Od er: Coleopte ra (Beetles) Family: Hydrophilidae (Water sca venger beetles)
punctulatum Family: Platypodidae (Pin-hole borers) Pin-hole borer A
Platypus sp.
Family: Staphylinidae (Rove beetles) Sa rgassum rove beetle
?Cafuis nauticus
Forest rove beetle
Stenus cf silvicola
Neglected rove beetle
Indigenous
Astenus neglectus
Flatwinged r ove beetle
Astenus depressipennis
Rove beetle A
Coproporus sp.
Rove beetle B
Cafinus sp.
Rove beetle C
Medon sp.
Weakhorned rove beetle
Medon debilicornis
Tinychested rove beetle
Medon microthorax
Family: Sca raba eidae (Scarabs) Sedge beetle
Rhisotrogus sp.
Indigenous
Terminalia beetle
Adoretes versutus?
Indigenous
Rhinoceros beetle
Oryctes monoceros
Alien/pest of C oconut palm
Flower sc arab
Protaetia aurichalcea
Indigenous/increased in abunda nce with establishment
Br oad scarab
Oxy omus palmarum
Grand scarab
Perssosoma grande
Endemic
of lowland forest
Family: Ela teridae (C lick beetles) Gia nt click bee tle
Megapenthes curtus
Indigenous
Click bee tle A
Me lanotus sp.
Indigenous
Br own click beetle
Cardiophorus lutosus
Gardinier’s click beetle
Cardiophorus gardinieri
Solitary click beetle
Porthmidus solitarius
Family: Pselaphida e (S hort-winged mould beetles) Obese mould beetle
Apheloplectus obesus
Endemic
Se ychelles m ould beetle
Trimic rus se yche llensis
Endemic
199
Family: Dermestidae (Woolly bears) Paratrogoderma mahensis
Indigenous
M ealybug rhyzobius
Rhy zobius lophanthae
Alien/feeds on m ealybugs
Little ora nge-fac ed ladybird
Exoc homus flavipes
Alien/feeds on m ealybugs
Chilocorus nigritus
Alien/im portant biocontrol agent of scale
M ahé woolly bear Family: Coccinellidae (Ladybirds)
Shiny black ladybir d
inse cts Family: Colydidae (Colydid beetles) Colobicones singularis
Endemic
Chlaenius bisignatus
Indigenous
Family: Car abidae (Ground beetles) Eye d ground beetle
Anilus sp. Family: Tenebrionidae (Tenebrionids) Se ychelles tenebrionid
Gonocephalum seychelle nsis
Indigenous
Shy tenebrionid
Gonocephalum micantipenne
Indigenous
Sc ott's tene brionid
Camarothelops sc otti
Indigenous
Br aue r's tenebr ionid Sa rgassum tenebrionid
Camarotheops braueri Alphitobius c renatus
Indigenous Indigenous
Pse udhadrus sp. Family: Sc olytidae (Shot-hole borers) Shot-hole borer A
Xyle borus cf piceus
Shot-hole borer B
Xyle borus cf. ferrugineus
Shot hole borer C
Xyle borus sp.
Shot hole borer D
Hypothene mus cf birmanus
Shot hole borer E
Cryphalus cf discre tus
Family: Nitidulidae ( Sap beetles) Flattened sap beetle
Stelidota e xplanata
Family: Rhizophagidae (R oot-eating beetles) Root-ea ting beetle A Root-ea ting beetle B
Rhizophagus sp. 1 Rhizophagus sp.2
Family: Ptilidae (Feather-winged beetles) Shelled f eather-winged beetle
Throscidium testaceum
Fea ther-winged beetle A
Ptinus sp.
Endemic
Family: Cr yptopha gida e (Silken fungus beetles) Cham pion’s silken fungus beetle
Hapalips championi
Kraatz’s silken fungus beetle
Eleusis k raatzi
Family: Oedemeridae (False blister bee tles) Yellow pollen beetle
Ananca sp.
Indigenous
? C eresium unic olor
Indigenous
? Acryptorrhynchus cf
Alien
Family: Cer ambycidae (Longhorn beetles) Br own longhorn Family: Cucurlionidae (Weevils) M ango weevil
mangiferae Sequinned weevil
? Acryptorrhynchus sp.
Indigenous?
Rice wee vil
Calandra ory zae
Alien
Or der: Diptera ( Flie s) Family: Muscidae (Houseflies) Compresse d house fly
200
Mydaea compressipalpis
Family: Micropeziidae Nereius alluaudi Family: Culicidae (Mosquitos) Single-striped mosquito
Aedes (Stegomyia)
Very common on Cousine/not known to vector any human disease on
unilineatus
the island
Suborder: Brachycera Family: Tabanidae (Horse flies) Turtle tabanid
Neavella albipectus
Family: Asilidae (Robber flies) Beach robber fly
Clinopogon
nicobarensis Order: Lepidoptera (Butterflies and moths) Family: Nymphalidae (Nymphalids) Common diadem Painted lady Family: Lycaenidae (Blues) Long-tailed blue African grass blue
Hypolimnas misippus
Indigenous
Vanessa cardui
Indigenous
Lampides boeticus Zizeeria knysna
Indigenous/ has decreased in abundance with growth of plain forest although benefits from tortoise grazing which maintains its open habitat
Family: Hesperidae (Skippers) Olive-haired skipper
Borbo borbonica
Indigenous
Family: Sphingidae (Hawkmoths) Convolvulus hawk moth
Agrius convolvuli
Indigenous/ migrant
Acherontia atropos
Indigenous/migrant
Achaea catella
Indigenous
Death’s head hawk moth Family: Noctuidae (Noctuids) Variegated night moth
Order: Hymenoptera (Bees, sawflies, ants and wasps) Suborder: Apocrita Family: Ichneumonidae (Ichneumons) Ichneumid wasp Family: Braconidae (Braconids)
Temelucha sp.
Apanteles Trioxys Family: Agaonidae (Fig
Apanteles sp. Trioxys sp.
wasps) Silvestri’s fig wasp Sycoscapter fig wasp Family: Vespidae (Wasps) Potter wasp, Mous zonn
Philocaenus silvestrii Sycoscapter sp.
Eumenes alluaudi
Endemic
201
Seychelles wood wasp Yellow wasp
Odynerus seychellensis Polistes olivaceus
Endemic Endemic/prefers open habitat and has declined with growth of the plain forest
Family: Apidae (Honey bees) Unicolour honey bee
Apis unicolor
Common pollinator of many plant species, especially Coromandel
Family: Anthophoridae (Carpenter bees) Afrotropical carpenter bee,
Xylocopa caffra
Important pollinator of various herbaceous plants
Mous brenzel Family: Formicidae (Ants) Black ponerine ant
Odontomachus
Alien/very abundant, especially under logs
Forest ponerine ant
troglodytes Hypoponera ragusai
Alien
Yellow sugar ant Sugar ant Little crazy ant
Camponotus grandidieri Camponotus maculatus Paratrechina longicornis
Indigenous Alien Alien
Crazy ant
Anoplolepis gracilipes
Alien/not yet recorded from Cousine, but included here as it is a major quarantine subject
Banana crazy ant Dark house ant Transparent house ant
Paratrechina bourbonica Technomyrmex albipes Tapinoma
Alien Alien Alien
Emma's ant
melanocephalum Strumigenys emmae Monomorium floricola
Alien Alien
Big-headed ant
Monomorium sechellense Pheidole megacephala
Indigenous? Alien/ very invasive/ attends Seychelles cottony cushion scale
Red forest ant
Tetramorium similimum
and mealybugs/major invasive of buildings Alien
Class: Crustacea (Crustaceans) Subclass: Cirripedia (Barnacles) Family: Lepadidae (Goose barnacles) Goose barnacle Family: Balanidae (Striped barnacles) Pink-striped barnacle
Lepas sp. Balanus sp.
Family: Tetraclitidae (Volcano barnacles) Volcano barnacle Tetraclita sp. Family: Chthamalidae Toothed barnacle Family: Balanidae Giant plated barnacle
Chthalamus sp. Austromegabalanus sp.
Subclass: Malacostraca (Higher crustaceans) Order: Isopoda (Isopods) Family: Oniscoidae (Sea slaters) Big-eye rock isopod Family: Trachelipodae
Ligia exotica? Nagurus nanus
Alien
Family: Armadillidae
202
Venezillo parvus
Indigenous
Reductioniscus costulatus Cubaris murina
Endemic Alien
Or der: Stomatopoda (Mantis shr imps) Family: Gonoda ctylidae (M antis shrimps) Br ight green m antis shrimp
Gondactylus cf falcatus
Among hard c orals
Or der: Decapoda (Crab s, lobsters and shr imps) Family: Pa linuridae (R ock lobsters) Pronghorn rock lobster
Palinurus penicillatus
Pa inted rock lobster
Palinurus versicolor
Longlegged rock lobster
Palinurus longipe s
Family: Pa laem onidae (Shrim ps) Diade ma shrimp
Peric limene s zanzibaricus?
Family: Alpheidae (Snapping shrim ps) Dardanus shrimp
Aretopsis amabilis?
Snapper shrimp
Alpheus sp.
Comm ensal with certain he rmit c rabs
Family: Penaeidae (C om mercial Prawns) Stripe d prawn
Penaeus canic ulatus
Family: Car idea ( Shrimps) Banded zebra shrimp Family: Coenobitidae (Land hermit cr abs)
Gnathophyllum sp.
Short handed hermit
C oenobita brevimanus
Pea rly hermit
C oenobita perlatus
Rough herm it
C oenobita rugosus
Family: Diogenidae ( Sea herm it crabs) Gia nt red herm it
Dardanus megistos
White-spotted herm it
Dardanus saguinolentus
Yellow-banded hermit
C libanarius viresc ens
Blue-eyed hermit
C alcinus laevimanus
White-eyed hermit
Genus unidentified
This herm it, a nd the three others listed
Purple- ba nded hermit
Genus unidentified
below, have me ntion as they are conspicuous
Gor geous he rmit
Genus unidentified
mem bers of the fauna
Sharp c lawed hermit
Genus unidentified
Family: Porcellanidae (Porcelain crabs) M arble porcelain c rab
?Perolisthes lamarcki
Family: Ma jida e (Decorator crabs) Yellow-decora tor cr ab
Genus unidentified
This and the other unidentified crabs listed
White-flecked decor ator c rab
Genus unidentified
below are currently never theless c onspicuous
Long-horned decorator crab
Genus unidentified
m embers of the fauna
Family: Portunidae (Swim ming cr abs) Snapper swimm ing crab
? Charybdis sp.
Red-spot swimm ing crab
T halamita sp.
Wide-e yed swimm ing cra b
? Thalamita sp.
Pink swimming c rab
Genus unidentified
Snapper swimm ing crab
c f Charybdis sp.
Family: Xanthidae (Coral crabs) Red eyed xanthid
Eriphia laevimanus
Large spotted cora l crab
C apilius maculatus
Eye d cor al crab
Atergatis subdentatus
Pretty poison crab
Z osymus aeneus
White spotte d xanthid
Genus unidentified
203
Grey bum p xa nthid
Genus unidentified
Wine xanthid
Genus unidentified
Tom ato xanthid
Genus unidentified
Straw leg xanthid
Genus unidentified
Short eye d xanthid
Genus unidentified
White spotte d cora l crab
Genus unidentified
Family: Grapsidae (S hore c rabs) Comm on rock cra b, Karkasay
Grapsus
Ver y c om mon day-tim e resident of rocks in the surf zone
tenuicrustatus Tan rock crab
Geograpsus crinipes
Mostly em erges at night to forage
Storm’s crab
Geograpsus stormii
Scarce on C ousine
Family: Gecarcinidae (Land cr abs) M angrove crab
Cardisoma carnifex
Family: Ocypodidae (Sta lk eyed crabs) Hor n-e yed ghost crab, Loulou
Ocypode
grangulo
ce ratophthalmus
hatchlings
Dark ghost crab, Loulou grangalo Pink ghost cra b
Ocypode cordimana Ocypode ryderi
Major predator of turtle eggs and hatchlings First appeared on Cousine in 2002/ predator of turtle
Com mon on the seashore/predator of turtle eggs and
hatchlings Class: Arac hnida (Spiders, scorpion s an d allie s) Or der: Pseudoscor pionida (Pse udoscorpions) Slow pseudoscorpion Withius piger
Com mon in leaflitter and has benefited from growth of plain fore st
Or der: Amb lypygi (W hip scorpions) Isla nd whip scorpion, Tarantine
Phrynicus scaber
arm e
Resident of the c ave in the north of the Island and under granite overhangs
Or der: Araneae (Spiders) Family: Araneidae (Orbweb weavers) Citric ola orbweb weaver
Cy rtophora citricola
Family: Clubionida e (Sac spiders) Hitchins’ sac spider
Clubiona hitchinsi
Endemic
Family: Corinnidae (Dark sac spiders) Grooved dark sac spider spider
Oedignatha
M ogamoga ’s da rk sac spider
Oedignatha
Greedy dark sac spider
Corinna gulosa
scrobiculata mogamoga Family: Cr yptothelidae (Litter spiders) Alluaud's litter spider
Cryptothe le alluaudi
Family: Ochyrocera tida e (Midget ground weavers) M inute ground weaver
Theotima minutissima
Family: Oonopidae (Dwarf hunting spiders)
204
M ahe dwarf hunting spider
Pelicinus mahe
Thr ee-hair dwarf hunting spide r
Lisna trichinalis
Lena's dwarf hunting spider
Opopaea le na
Desert dwarf hunting spider
Opopaea de serticola
Keely’s dwarf hunting spider
Cousinea keelyi
Cuban dwarf hunting spider
Brignolia cubana
Endemic
Pelted dwarf hunting spider Velox dwarf hunting spider
Ischnothyreus peltifer Ischnothyneus velox
Kilikus' dwarf hunting spider Three-chined dwarf hunting spider
Oonopinus kilikus Gamasomorpha trichinalis
Endemic
Grooved dwarf hunting spider Family : Oecobidae (Star-legged spiders)
Hedypsilus culiculus
Endemic
Beautiful star-legged spider spider Marathaus' star-legged spider
Tarapaca concinnus Maitreja marathaus
Family: Pholcidae (Daddy longlegs) House daddy longlegs
Smeringopus pallidus
Faurot’s daddy longlegs Globose daddy longlegs Delicate daddy longlegs
Microfolcus fauroti Physocyclus globosus Hedypsilus culiculus
Endemic
Family: Prodidomidae (Long-spinneret ground spiders) Stella’s ground spider Prodidomus stella Family: Theridiidae (Cobweb spiders) Florida cobweb spider Adamson's cobweb spider
Coleosoma floridana Coleosoma adamsoni
Clabnum cobweb spider Theridion clabnum Dirty cobweb spider Theridion scorinum Family: Mysmenidae (Spurred orb-weavers) Elsa's spurred orb-weaver Family: Linyphiidae (Money spiders)
Microdipoena elsae
Palmar money spider Three-tailed money spider
Microbathyphantes palmarius Theoa tricaudata
Remiform money spider Benoit’s money spider
Neonesiotes remiformis Nesioneta benoiti
Endemic
Family: Schizomidae Schizomida (3 spp.) Family: Tetragnathidae (Long-jawed spiders) Palm spider, Bib
Nephila inaurata
Little orb spider Marginate spider Family: Lycosidae (Wolf spiders)
Drexilia bifida Tetragnatha marginata
Very common and conspicuous member of the Seychelles fauna
Seychelles wolf spider Bristowiella seychellensis Urban wolf spider Trochosa urbana Family: Gnaphosidae (Flat-bellied ground spiders) Mouse ground spider Camillina ground spider
Xerophaeus espoir Camillina cordifera
Family: Heteropodidae (Crab spiders) Hunting crab spider Family: Selenopidae (Wall spiders)
Heteropoda venatori
Secretive spider Family: Sparassidae (Giant crab spiders)
Selenops secretus
Hunting crab spider
Heteropoda venatoria
205
Family: Sa lticidae (Jumping spiders) Ada msons jumping spider
Hasarius adamsonii
Active jumping spider
Heliophanus activus
Acute jumping spider
Hyllus acutus
Pa ykull’s jumping spider
Plexippus paykulli
Two-spot jumping spider
Menemerus biv ittatus
Black-footed jum ping
Microbianor nigritarsis
spider Family: Sc ytodidae (Spitting spider s) Souer’s spitting spider
Soue ria souer
Yellow spitting spider
Scytodes fusca
Sub or der: Acariform es (Mites a nd tic ks) Family: Ixodida e (Tic ks) Br own bird tic k
Amblyomma loc ulosum?
Para sitizes Se ychelles m agpie robin and young Sooty tern
Phylu m: Echinodermat a (Sea cu cumb ers, sea urc hin s and starfish) Class: Holothu roidea (S ea cucumber s) Family: Holothuriidae Black sea cucumber
Holothuria atra
Red-dash sea cucumber
Holothuria arenicola?
Variable sea cucumbe r
Actinopyga mauritiana
Family: Stic hopodidae Dark green warted sea
Stichopus chloronotus
cucumber Class: Echinoid ea (Sea ur chins) Family: Dia dem atidae Black needle urchin
Diadema savignyi
Banded urchin
Echinothrix calamaris
Stout needle urchin
Echinothrix diade ma
Slate pencil urchin
Heteroce ntrotus sp.
Common on compa cted c ora l r ubble, and ha s increased since the great bleac jhing event
Family: Cidaridae Banded club-urchin
Eucidaris metularia
Family: Echinometridae Ova l black urchin
Echinometra mathaei
Protea urchin
C olobocentrorus atratus
Family: Toxopneustida e Red-a nd-white urchin
Tripneustes ve ntricosus?
Gia nt short-spined urc hin
Salmacis sp.
Class: Aster oidea (S tarf ish) Family: Ophiasteridae (Starfish) Comm on sta r
Linckia laevigata
Eye d star
N eoferdina offreti ?
Class: Ophiuroidea (Brittle stars) Family: Ophioc omidae
206
Granular brittle star
Ophiocoma
Orange -and-black brittle star
scolopendrina? Ophiocoma sp.
Phylum: Chordata (Chordates) Subphylum: Vertebrata (Vertebrates) Class: Pisces (Fish) Subclass: Chondrichthyes (Sharks and rays) Order: Orectolobiformes Family: Ginglymostomatidae (Nurse sharks) Nurse shark Family: Rhincodontidae (Whale shark) Whale shark Order: Carcharhiniformes
Nebrius ferrugineus Rhincodon typus
Family: Carcharhinidae (Requeim sharks) Milk shark Reef whitetip shark
Rhizoprionodon acutus? Triaenodon obesus
Grey reef shark, Reken bar Silvertip shark, Reken waro
Carcharhinus amblyrhyncos Carcharhinus albimarginatus
Reef blacktip shark, Reken nwanr Tiger shark, Reken marto Lemon shark
Carcharhinus melanopterus Galeocerdo cuvier Negaprion acutidens
Family: Sphyrinidae (Hammerhead sharks) Hammerhead shark
Sphyrna mokkaran
Rare visitor to Cousine
Order: Rajiformes Family: Rhinobatidae (Guitarfishes) White-spotted guitarfish, Reken violon
Rhynochobatus djiddensis
Order: Myliobatiformes Family: Myliobatidae (Eagle rays) Spotted eagle ray, Lare sousouri
Aetobatus narinari
Family: Dasyatidae (Stingrays) Flapnose ray Bluespotted ribbontail ray
Rhinoptera javanica Taeniura lymma
Porcupine ray Subclass: Osteichthyes (Bony fishes)
Urogymnus asperrimus?
Order: Anguilliformes Family: Muraenidae (Morays) Whiteface moray
Echidna leucotaenia
Snowflake moray Giant moray
Echidna nebulosa Gymnothorax javanicus
Masked moray Salt and pepper moray Honeycomb moray
Gymnothorax breedeni Gymnothorax eurostus Gymnothorax favagineus
Yellow margined moray Undulated moray Saddled snake eel
Gymnothorax flavimarginatus Gymnothorax undulatus Leiuranus semicinctus
Geometric moray Peppered moray
Siderea grisea Siderea picta
Order: Clupeiformes Family: Clupeidae (Herrings, sprats and sardines) Gold spot herring, Sardin ordiner Herkosichthys quadrimaculatus Blue sprat
Spratelloides delicatulus
207
Order: Gonorynchiformes Family: Chanidae (Milkfish) Milkfish, Libine Order: Siluriformes Family: Plotosidae (Eel catfishes)
Chanos chanos
Striped catfish
Plotusus lineatus
Family: Atherinidae (Silversides) Hardy silversides Silversides Order: Beloniformes
Antherinomorus lacunosus? Hypoatherina sp.
Family: Belonidae (Needlefishes) Needlefish Houndfish
Strongylura cf leiura Tylosurus crocodilus
Family: Hemirhamphidae (Halfbeaks) Insular halfbeak
Hyporhamphus affinis
Family : Exocoetidae (Flying fishes) Sailfin flying fish
Parexocoetus
Spotfin flying fish
brachypterus? Cheilopogon furcatus?
Order: Beryciformes Family: Holocentridae (Soldierfishes and squirrelfishes) Myripristis adusta Bronze soldierfish Red soldierfish Seychelles soldierfish Violet soldierfish
Myripristis murdjan Myripristis seychellensis Myripristis violacea
Bloodspot squirrelfish Crown squirrelfish
Neoniphon sammara Sargocentron diadema
Tailspot squirrelfish Blackspot squirrelfish
Sargocentron caudimaculatum Sargocentron
Seychelles squirrelfish
melanospilos Sargocentron seychellense
Long-jawed squirrel fish, lion Family: Aulostomidae (Trumpetfishes) Trumpet fish
Endemic
Sargocentron spiniferum Aulostomus chinensis
Family: Fistulariidae (Cornetfishes) Cornetfish, tromp Family: Syngnathidae (Pipefishes) Sculptured pipefish
Fistularia commersonii Choeroichthys sculptus
Order: Scorpaeniformes Family: Scorpaenidae (Scorpionfishes) Lionfish
Pterois miles
Clearfin lionfish Tassled scorpionfish
Pterois radiata Scorpaenopsis oxycephala
Yellow-spotted scorpionfish Stonefish
Sebasapistes cyanostigma Synanceia verrucosa
Order: Cyprinodontiformes Family: Aplocheilidae (Annual killifishes) Playfair’s panchax (killifish)
208
Pachypanchax playfairi
Inigenous; introduced into tortoise ponds in 2008 to
Order: Perciformes Family: Kuhliidae (Flagtails) Barred flagtail Family: Serranidae (Groupers and allies) Redmouth grouper
Kuhlia mugil Aethaloperca rogaa
Commercially harvested around Cousine
Sea goldie Peacock grouper, Vyey kwizinyen
Anthias (Pseudanthias) squamipinnis Cephalopholis argus
Commercially harvested around Cousine
Leopard grouper Coral hind, Vyey zannan
Cephalopholis leopardus Cephalopholis miniata
Commercially harvested around Cousine Commercially harvested around Cousine
Darkfin grouper Tomato grouper, Msye angar Blackfin grouper, Vyey rooz
Cephalopholis nigripinnis Cephalopholis sonnerati Epinephelus fasciatus
Commercially harvested around Cousine
Brownspotted grouper, Vyey makonde
Epinephelus chlorostigma
Whitespotted grouper Hexagon grouper Bigspot grouper
Epinephelus caeruleopunctatus Epinephelus hexagonatus Epinephelus macrospilos
Commercially harvested around Cousine Commercially harvested around Cousine Commercially harvested around Cousine
Blackspot grouper Honeycomb grouper
Epinephelus melanostigma Epinephelus merra
Commercially harvested around Cousine Commercially harvested around Cousine
White-blotched grouper, Vyey plat Halfmoon grouper Foursaddle grouper
Epinephelus multinotatus Epinephelus rivulatus Epinephelus spilotoceps
Commercially harvested around Cousine Commercially harvested around Cousine
Potatoe grouper Sixstripe soapfish Saddleback coral grouper, Vyey
Epinephelus tukula Grammistes sexlineatus Plectropomus laevis
babonn sesil Lyretail grouper, Krwasan
Variola louti
Family: Theraponidae (Grunters) Crescent-banded grunter Family: Priacanthidae (Bigeyes)
Terapon jarbua
Glass-eye Goggeleye
Priacanthus cruentatus Priacanthus hamrur
Family: Apogonidae (Cardinalfishes) Blackbanded cardinalfish
Apogon cookii?
Yellow-striped cardinalfish Broad-striped cardinalfish
Apogon cyanosoma Apogon
Orange-lined cardinalfish Lined cardinalfish
taeniophorus/angustatus Archamia fucata Cheilodipterus artus
Large-toothed cardinalfish Family: Haemulidae (Sweetlips) Slatey sweetlips, Kaptenn di por
Cheilodipterus macrodon
Dusky sweetlips Giant sweetlips
Plectorhincus chubbi Plectorhincus obscurus
Oriental sweetlips, Vyey sesil
Plectorhincus orientalis
Commercially harvested around Cousine
Diagramma pictum
Once common/has declined since the great bleaching event of 1998
209
Spotted sweetlips
Plectorhincus picus
Sombre sweetlips Family: Lutjanidae (Snappers) Green jobfish, Zob gri
Plectorhincus schotaf Aprion virescens
Twinspot snapper, Vara vara
Lutjanus bohar
Snubnose emporer Ehrenberg's snapper
Lutjanus borbonicus (= mahsenoides) Lutjanus ehrenbergi
Black-spot snapper, Ziblo Humpback snapper, Terez
Lutjanus fulviflammus Lutjanus gibbus
Blue-lined snapper, Madras Bigeye snapper Onespot snapper, Semiz
Lutjanus kasmira Lutjanus lutjanus Lutjanus monostigma
Emperor snapper, Bourzwa
Lutjanus sebae
Yellow-lip emporer Black snapper Family: Caesionidae (Fusiliers)
Lutjanus xanthocheilus Macolor niger
Scissor-tailed fusilier, Makro kannal Lunar fusilier Yellowback fusilier
Caesio caerulaureus Caesio lunaris Caesio teres
Yellowtop fusilier Twinstripe fusilier
Caesio xanthonota Pterocaesio marri
Bluestreak fusilier Dwarf fusilier Family: Lethrinidae (Emperors)
Pterocaesio tile Dipterygonotus balteatus
Yellowspot emporer Blue-lined large-eye bream, Kapitan
Gnathodentax aurolineatus Gymnocranius grandoculis
blan Red-axil emperor, Gel de van
Lethrinus conchyliatus
Yellowfin emporer, Laskar Blackspot emporer, Enbalasann
Lethrinus crocineus Lethrinus harak
Pink-ear emperor, Zekler
Lethrinus lentjan
Sky emporer, Madam Beri Smalltooth emporer Spangled emporer, Kapitan rouge
Lethrinus mahsena Lethrinus microdon Lethrinus nebulosus
Longface emporer, Bekbek
Lethrinus olivaceus
Redgill emporer Variegated emporer, Baksou Bigeye emporer
Lethrinus rubrioperculatus Lethrinus variegatus Monotaxis grandoculis
Commercially harvested around Cousine
Commercially harvested around Cousine
Commercially harvested around Cousine Commercially harvested around Cousine Commercially harvested around Cousine
Commercially harvested around Cousine
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Family: Nemipteridae (Spinecheeks) Bridled spinecheek Family: Kyphosidae (Rudderfishes) Highfin rudderfish Lowfin rudderfish
Scolopsis frenatus
Kyphosus cinerascens Kyphosus vaigiensis
Family: Ephippidae (Spadefishes) Batfish, Poul do Longfin spadefish Family: Monodactylidae
Platax orbicularis Platax teira
(Monos) Mono, Lime
Monodactylus argenteus
Family: Gerreidae (Mojarras) Blackfin pursemouth
Gerres mojarra
Family: Mullidae (Goatfishes) Dash-and-dot goatfish, Pouz tas Two-barred goatfish
Parupeneus barberinus
Yellowsaddle goatfish Indian goatfish Longbarbel goatfish
Parupeneus cyclostomus Parupeneus indicus Parupeneus macronema
Rosy goatfish Yellowstripe goatfish
Parupeneus rubescens Mulloidichthys
Yellowfin goatfish
flavolineatus Mulloidichthys vanicolensis
Parupeneus bifasciatus
Family: Pomacanthidae (Angelfishes)
Three-spot angelfish
Apolemichthys trimaculatus x xanthurus Apolemichthys
African pygmy angelfish
trimaculatus Centropyge acanthops
Many-spined angelfish Emporer angelfish Semicircle angelfish
Centropyge multispinis Pomacanthus imperator Pomacanthus
Armitage angelfish
semicirculatus Yellow angelfish Pomacanthus sulphurus Family: Chaetodontidae (Butterflyfishes) Threadfin butterflyfish
Chaetodon auriga
Saddleback butterflyfish Spotted butterflyfish Lined butterflyfish
Chaetodon falcula Chaetodon guttatissimus Chaetodon lineatus
Yellowhead butterflyfish Black-backed
Chaetodon lunula Chaetodon melannotus
butterflyfish
Not as common today as it was prior to the great bleaching event of 1998
Never common around Cousine, this coralivorous species has now disappeared, possibly temporarily, following the great bleaching event of 1998
211
Chevroned butterflyfish
Chaetodon trifascialis
Redfin butterflyfish
Chaetodon trifasciatus
Raccoon butterflyfish
Chaetodon xanthocephalus Chaetodon
Zanzibar butterflyfish
Although common on Cousine’s reefs prior to the great bleaching event of 1998 this coralivorous species species has now disappeared, possibly only temporarily As for the Redfin butterflyfish Prior to 1998 this species was common, but has since disappeared, possibly only temporarily
zanzibariensis Family: Carangidae (Jacks and trevallys) Yellow-tail scad Bar jack
Atule mate Carangoides ferdau
Yellow-dotted trevally, Karang plat
Carangoides fulvoguttatus
Commercially harvested around Cousine
Yellow-spotted trevally
Commercially harvested around Cousine
Bar-cheek trevally
Carangoides orthogrammus Carangoides
Bluefin trevally,
plagiotaenia Caranx
Karang ver Brassy trevally Bigeye trevally
melampygus Caranx papuensis Caranx
Giant trevally, Karang ledan
sexfasciatus Caranx ignobilis
Golden trevally
Gnathanodon speciosus
Leatherback Small-spotted pompano
Scomberoides lysan Trachinotus
Silver pompano
bailloni Trachinotus blohii
Large-spotted pompano Rainbow runner, Galate Family: Echeneidae (Sharksuckers) Sharksucker
Trachinotus botla Elagatis bipinnulata
Commercially harvested around Cousine Commercially harvested around Cousine
Commercially harvested around Cousine
Commercially harvested around Cousine
Echeneis naucrates
Family: Coryphaenidae (Dolphinfishes) Dorado, Dorad
Coryphaena hippurus
Family: Cirrhitidae (Hawkfishes) Pixie hawkfish Arc-eye hawkfish Freckled hawkfish
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Cirrhitichthys oxycephalus Paracirrhites arcatus Paracirrhites forsteri
Commercially harvested around Cousine
Family: Pempheridae (Sweepers) Schwenk’s sweeper
Pempheris schwenkii
Vanikoro sweeper Family: Pomacentridae (Damselfishes)
Pempheris vanicolensis
Yellow-tail sergeant Banded sergeant Scissor-tail sergeant
Abudefduf notatus Abudefduf septemfasciatus Abudefduf sexfasciatus
Black-spot sergeant Indo-Pacific sergeant
Abudefduf sordidus Abudefduf vaigiensis
Skunk anemonefish Seychelles anemonefish Black-axil chromis
Amphiprion akallopisos Amphiprion fuscocaudatus Chromis atripectoralis
Two-tone chromis Doublebar chromis
Chromis dimidiata Chromis opercularis
Ternate chromis Webers chromis Twospot demoiselle
Chromis ternatensis Chromis weberi Chrysiptera biocellata
Grey demoiselle Surge demoiselle
Chrysiptera glauca Chrysiptera leucopoma
Onespot demoiselle Humbug dascyllus Indian dascyllus
Chrysiptera unimaculata Dascyllus aruanus Dascyllus carneus
Longfin bannerfish Fusilier damsel Dick’s damsel
Heniochus acuminatus Lepidozygus tapienosoma Plectroglyphidodon dickii
Brighteye damsel Johnston damsel
Plectroglyphidodon imparipennis Plectroglyphidodon johnstonianus
Jewel damsel Whiteband damsel Caerulean damsel
Plectroglyphidodon lacrymatus Plectroglyphododon leucozonus Pomacentrus caeruleus
Blue damsel Sulphur damsel
Pomacentrus pavo Pomacentrus sulfureus
Family: Labridae (Wrasses) Blue-spotted wrasse Yellowtail wrasse
Anampses caeruleopunctatus Anampses meleagrides
Yellowbreasted wrasse Axilspot hogfish, Domeng
Anampses twisti Bodianus axillaris
Diana's hogfish, Domeng Floral wrasse Bandcheek wrasse
Bodianus diana Cheilinus chlorourus Oxycheilinus diagrammus
Red-banded wrasse, Kalam Snooty wrasse Tripletail wrasse
Cheilinusfasciatus Cheilinus oxycephalus Cheilinus trilobatus
Humphead wrasse Cigar wrasse, ies madanm
Cheilinus undulatus Cheilio inermis
Exquisite wrasse African coris Clown coris
Cirrhilabrus exquisitus Coris africana Coris aygula
Spottail coris Queen coris
Coris caudimaculata Coris frerei
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214
Slingjaw wrasse Indian Ocean bird wrasse
Epibulus insidiator Gomphosus caeruleus
Checkerboard wrasse Dusky wrasse Nebulous wrasse
Halichoeres hortulanus Halichoeres marginatus Halichoeres nebulosus
Zigzag wrasse, Tanmaren Barred thicklip wrasse
Halichoeres scapularis Hemigymnus fasciatus
Blackedge thicklip wrasse Ring wrasse Candycane longface wrasse
Hemigymnus melapterus Hologymnosus annulatus Hologymnosus doliatus
Bicolor cleaner wrasse Bluestreak cleaner wrasse
Labroides bicolor Labroides dimidiatus
Tubelip wrasse Vermiculate wrasse Rockmover wrasse
Labrichthys unilineatus Macrophyringodon bipartitus Novaculichthys taeniourus
Striated wrasse Sixline wrasse
Pseudocheilinus evanidus Pseudocheilinus hexataenia
Bluelined wrasse Red-shoulder wrasse Three-ribbon wrasse
Stethojulis albivittata Stethojulis bandanensis Stethojulis strigiventer
Twotone wrasse Sixbar wrasse Goldbar wrasse
Thalassoma amblycephalum Thalassoma hardwicke Thalassoma hebraicum
Surge wrasse Fivestripe wrasse
Thalassoma purpureum Thalassoma quinqueittatum
Blackspot pygmy wrasse Family: Scaridae (Parrotfishes) Bumphead parrotfish, Filanbaz
Wetmorella nigropinnata Bolbometopon muricatum
Stareye parrotfish Bicolor parrotfish
Calotomus carolinus Cetoscarus bicolor
Redtail parrotfish Indian Ocean longnose parrotfish, Kakatwa brino
Chlorurus japanensis Hipposcarus harid
Black crescent parrotfish Captain parrotfish
Scarus atrilunula Scarus enneacanthus
Greenbelly parrotfish, Kakatwa ver Bridled parrotfish
Scarus falcipinnis
Bluebarred parrotfish, Kakatwa blan Violet-lined parrotfish
Scarus ghobban
Swarthy parrotfish Greenthroat parrotfish
Scarus niger Scarus prasiognathus
Redlip parrotfish, Kakatwa rouz Russell’s parrotfish Dusky-capped parrotfish
Scarus rubroviolaceus Scarus russelli Scarus scaber
Tricolor parrotfish Greenlip parrotfish
Scarus tricolor Scarus viridifucatus
Family: Mugilidae (Mullets) Fringelip mullet, Mile soter
Crenimugil crenilabrus
Scarus frenatus
Scarus globiceps
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Family: Polynemidae (Threadfins) Sixfeeler threadfin
Polydactylus sexfiles
Family: Sphyraenidae (Barracudas) Yellowtail barracuda Blackfin barracuda
Sphyraena flavicauda Sphyraena qenie
Commercially harvested around Cousine
Great barracuda, Tazar Pickhandle barracuda, Bekin Sawtooth barracuda
Sphyraena barracuda Sphyraena jello Sphyraena putnamiae
Commercially harvested around Cousine Commercially harvested around Cousine Commercially harvested around Cousine
Blackspot barracuda, Bekin Family: Blennidae (Blennies)
Sphyraena forsteri
Commercially harvested around Cousine
Maned rockskipper Blackspotted rockskipper Leopard blenny
Damania anjouana Entomacrodus striatus Exalias brevis
Dussumier’s rockskipper Rippled rockskipper
Istiblennius dussumieri Istiblennius edentulus
Picture rockskipper Scale-eating fangblenny Family: Tripterygidae (Triplefins)
Istiblennius gibbifrons Plagiotremis tapienosoma
Hourglass triplefin Blackfin triplefin
Enneapterygius elegans Helcogramma fuscopinna
Family: Gobidae (Gobies) Frill-goby A Spotted frill-goby
Bathygobius sp. Bathygobius cyclopterus
Frill-goby B Goby A Citron goby
Bathygobius coalitus Cirripectis sp. Gobiodon citrinus
Goby B Blackfin dartfish
Callogobius sp. Ptereleotris evides
Zebra dartfish Family: Acanthuridae (Surgeonfish)
Ptereleotris zebra
Eyestripe surgeon Powder blue surgeon
Acanthurus dussumieri Acanthurus leucosternon
Striped surgeon Blackstreak surgeon Lieutenant surgeon
Acanthurus lineatus Acanthurus nigricauda Acanthurus tennenti
Bluelined surgeon Convict surgeon
Acanthurus nigroris Acanthurus triostegus
Yellowfin surgeon, Sirizyen Two-spot bristletooth Striped bristletooth
Acanthurus xanthopterus Ctenochaetus binotatus Ctenochaetus striatus
Goldring bristletooth Humpback unicornfish Spotted unicornfish
Ctenochaetus strigosus Naso brachycentron Naso brevirostris
Orange-spine unicornfish Singlespine unicornfish
Naso lituratus Naso thynnoides
Bluespine uniicornfish Bignose unicornfish Palette surgeonfish
Naso unicornis Naso vlamingii Paracanthurus hepatus
Desjardins sailfin tang
Zebrasoma desjardinii
215
Brushtail tang Family: Zanclidae (Moorish idols)
Zebrasoma scopas
Moorish idol Family: Siganidae (Rabbitfishes) Forktail rabbitfish, Kordonnyen
Zanclus cornutus Siganus argenteus
soulfanm Blackeye rabbitfish Rivulated rabbitfish, Kordonnyen
Siganus puelloides Siganus rivulatus
canalo Stellate rabbitfish, Kordonnyen
Siganus stellatus
margrit African whitespotted rabbitfish, Kordonnyen blan Coral rabbitfish, Kordonnyen lafimen
Commercially harvested around Cousine
Siganus corallinus
Family: Scombridae (Tunas and mackerels) Yellowfin tuna, Ton Zonn Eastern little tuna, Bonit fol
Thunnus albacares Euthynnus affinis
Commercially harvested around Cousine
Double-lined mackerel Dogtooth tuna, Ton ledan
Grammatorcynos bilineatus Gymnosarda unicolor
Commercially harvested around Cousine Commercially harvested around Cousine
Wahoo, Kingfish, Wahoo Family: Istiophoridae (Sailfishes) Sailfish
Acanthocybium solandri
Commercially harvested around Cousine
Istiophorus platypterus
Order: Tetraodontidae (Triggerfishes) Family: Balistidae (Triggerfishes) Starry triggerfish, Bours
Abalistes stellatus
Moustache triggerfish Indian triggerfish
Balistoides viridescens Melichthys indicus
Black triggerfish Picassofish Wedge Picassofish
Melichthys niger Rhinecanthus aculeatus Rhinecanthus rectangulus
Halfmoon triggerfish Bridled triggerfish
Sufflamen chrysopterus Sufflamen fraenatus
Family: Monacanthidae (Filefishes) Broom filefish
Amanses scopas
Barred filefish Wire-net filefish
Cantherhines dumerilii Cantherhines pardalis
Long-nose filefish Blacksaddle mimic Blackbar filefish
Oxymonocanthus longirostris Paraluteres prionorus Pervagor janthinosoma
Family: Ostraciidae (Trunkfishes) Thornback cowfish Yellow boxfish
Lactoria fornasini Ostracion cubicus
Spotted trunkfish Family: Tetraodontidae
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Siganus sutor
Commercially harvested around Cousine
Ostracion meleagris
(Pufferfishes) Map puffer Guineafowl puffer
Arothron mappa Arothron meleagris
Black-spotted puffer Bennett's sharp-nosed puffer
Arothron nigropunctatus Canthigaster bennetti
Spotted toby
Canthigaster solandri
179
Black-saddled toby
Canthigaster vale ntini
Family: Diodontidae (Porc upine fishes) Porcupinefish
Diodon hystrix
Black blotched
Diodon liturosus
porcupinef ish Class: Reptilia (Reptiles) Or der: Che lonia (Turtles and t ortoise s) Family: Chelonidae (Turtles) Green turtle, Torti d'mer
Chelonia mydas
A rare visitor to Cousine, whe re it occa sionally breeds
Hawksbill turtle, Torti ca ret
Ere tmoc helys imbricata
Since intense restoration of C ousine bega n, its numbers ha ve inc reased and appear to be c urre ntly stabilized
Family: Testudinidae (Tortoises) Aldabran gia nt tor toise, Torti
Aldabrache lys gigantea
This introduced c ollection of individua ls is to date a non-breeding popula tion, with some of the individuals even showing som e characteristics of the Seyc helles giant tortoise and Arnold’s giant tortoise
Or der: Squamata (L izards and Snakes) Sub or der: Sauria (Lizar ds) Family: Gekkonidae (Geckos) Stripe less da y gecko, Liza
Phelsuma astriata
Endem ic
ver Br onze gecko, M aguya
Ailurony x seychellensis
Endem ic
Pa cific gecko, Liz a disik
Gehyra mutilata
Alien
Se ychelles sucker-ta iled
Urocoty ledon
Endem ic
gecko, Liza disik
inexpectata
Family: Scincidae Se ychelles skink, Lezar sek
Mabuya seychellensis
Endem ic
Wright’s skink, Lezar
Mabuya wrightii
Endem ic
Pamelae scinus
Endem ic
tengteng Gardiner’s skink
gardineri Sub or der: Ser pentes (Sn akes) Family: Typhlopidae Flowerpot snake
Ramphotyphlops
Alien
braminus Family: Colubridae Se ychelles wolf-snake,
Lyc ognathophis
Koulev zonn Family: Elapida e (Cobras, garter snakes, se a snakes and others)
seychellensis
Yellow-bellied sea snake
Pelamis platurus
Endem ic
Indigenous
Class: Aves (Birds) Or der: Procellariforme s Family: Procellar idae (Shearwater s) Audubon’s Shearwater, R iga
Puffinus lherminieri
Wedgetaile d shearwater,
Puffinus pacificus
Present all year, breeds May-December/ numbers have increa sed
Fouke
chlororhync hus
substantia lly since eradication of cats and cessation of poaching
Present all year, breeds May-December/has increa sed sinc e eradication of cats and cessation of poa ching
Or der: Pelecanifor mes Family: Phaeothontida e (Tropicbirds)
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217
Red-tailed tropicbird, Payanke lake rouz White-tailed tropic bird, Payanke
Phaethon rubricauda Phaethon lepturus
Sporadic, non-breeding visitor May-December Breeds all year, with a strong population on Cousine
Family: Sulidae (Gannets and Boobies) Masked Booby
Sula dactylatra
Vagrant
Family: Fregatidae (Frigatebirds) Greater frigate bird; Fregate
Fregata minor
Visitor all year
Lesser frigate bird, Fregat Order: Ciconiiformes Family: Ardeidae (Herons, egrets and bitterns)
Fregata ariel
Sporadic visitor/May-February
Grey heron; Florentin Cattle egret, Madanm paton
Ardea cinerea Bubulcus ibis sechellarum
Vagrant/April and November Sporadic visitor/most of the year
Green-backed heron, Makak or Manik
Butorides striatus digens
Black-crowned night heron
Nycticorax nycticorax
Resident/has bred in April and AugustSeptember Vagrant/June
Madagascan pond heron Eurasian bittern
Ardeola idea Botaurus stellaris
Vagrant/March Vagrant/November-December
Cinnamon bittern Order: Falconiformes Family: Accipitridae
Ixobrychus cinnamomeus
Vagrant/August
Black kite Honey buzzard Family: Falconidae
Milvus migrans migrans Pernis apivorus
Vagrant/December Vagrant/June
Eurasian hobby Eleonora’s falcon
Falco subbuteo Falco eleonorae
Vagrant/December-February Vagrant/April and December
Amur falcon Red-footed kestrel
Falco amurensis Falco vespertinus
Vagrant/December to February Vagrant/December to February
Order: Gruiformes Family: Rallidae (Rails, moorhens and kin) Domestic chicken, Poul
Gallus domesticus
Eradicated
Moorhen, Pouldo Order: Charadriiformes Family: Charadriidae (Plovers)
Gallinula chloropus
Present all year round/breeds April-January
Common ringed plover, Zalwet Lesser sandplover, Zalwet
Charadrius hiaticula Charadrius mongolus atrifrons
Occasional visitor Occasional visitor/October-April
Greater Sandplover, Zalwet Grey plover, Zalwet
Limosa leschenaultii Pluvialis squatarola
Occasional visitor/December-April Occasional vistor/August-April
Pacific golden plover Pluvialis fulva Family: Scolopacidae (Sandpipers, stints and curlews) Turnstone, Bez-ros Arenaria interpres Terek sandpiper
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Xenus cinereus
Vagrant Present all year round but does not breed on Cousine Vagrant
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Family: Dromadidae (Crab plover) Crab plover, Kavalye
Dromas ardeola
Family: Laridae (Skuas, Gulls, Terns, Noddies) Arctic skua Stercorarius parasiticus Little tern Sterna albifrons Gull-billed tern Greater crested tern, Golan sardinn
Gelochelidon nilotica Sterna bergii
Lesser crested tern Roseate tern, Dyaman Common tern
Sterna bengalensis Sterna dougallii Sterna hirundo
Black-naped tern, Dyaman Sooty tern, Golet
Sterna sumatrana Sterna fuscata nubilosa
Common, non-breeding visitor/August-May
Vagrant
Re-established naturally on Cousine, after an absence of 30 years, following removal of cats, restoration of its open habitat and cessation of poaching
Bridled tern, Fanse
Sterna anaethetus antarctica
Saunder’s tern White tern, Golan blan Brown noddy, Makwa
Sterna saundersi Gygis alba monte Anous stolidus pileatus
Lesser noddy, Kordonnyen, Kelek Anous tenuirostris tenuirostris Lesser black-backed gull Larus fuscus Family: Columbidae (Doves and pigeons)
Strong breeding colony on Cousine Strong breeding colony on Cousine Major breeding colony on Cousine Occasionally seen on Cousine
Seychelles turtle dove, Tourtrel dezil Madagascar turtle dove, Tourtrel dezil
Streptopelia picturata rostrata Streptopelia picturata picturata
Madagascar turtle dove, Seychelles turtle dove hybrid, Tourtrel dezil Seychelles blue pigeon, Pizon olande
Streptopelia picturata picturata x Streptopelia picturata rostrata Alectroenas pulcherrima
Endemic and breeds on Cousine/has benefited
Barred ground dove, Tourtrel koko
Geopelia striata
from reforestation of the plain Alien but appears to pose no threat
Family: Coraciidae (Rollers) Eurasian roller
Coracias garrulus
Occasional visitor
Family: Meropidae (Bee eaters) Bluecheeked bee eater
Merops persicus
Occasional visitor
Family: Cuculidae (Cuckoos) European cuckoo Asian lesser cuckoo
Cuculus canorus Cuculus poliocephalus
Occasional visitor Occasional visitor
Family: Tytonidae (Owls) Barn owl, Ibou
Tyto alba affinis
An alien which has been eradicated from Cousine but requires continual monitoring
Family: Apodidae (Swifts) Little swift
Apus affinis
Occasional visitor
Hirundo rustica
Occasional visitor
Family: Hirundinidae (Swallows) European swallow Family: Oriolidae (Orioles)
European golden oriole Oriolus oriolus Family: Muscicapidae (Chats and robins) Seychelles magpie robin, Pi santez
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Re-established on Cousine following removal of cats on restoration of its open habitat
Copsychus sechellarum
All three forms occur on Cousine
Vagrant/November Successfully introduced
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Common redstart Family: Sylvidae (Warblers)
Phoeniculus phoeniculus
Occasional visitor
Seychelles warbler, Timerl dezil
Acrocephalus sechellensis
An endemic which has been successfully introduced onto Cousine
Motacilla alba Motacilla flava
Occasional vagrant Occasional vagrant
Family: Motacillidae (Wagtails and pipits) White wagtail Yellow wagtail
Tree pipit Anthus trivialis Family: Sturnidae (Starlings and mynahs) Acridotheres tristis Indian mynah, Marten
Occasional vagrant Alien, constantly eradicated from Cousine as it poses a threat to endemic birds
Family: Nectarinidae (Sunbirds) Nectarinia dussumieri
Endemic/regularly seen on Cousine even close to buildings
Seychelles white-eye, Zwazo linet Family: Ploceidae (Fodies)
Zosterops modestus
Successfully introduced to Cousine in 2007
Seychelles fody, Tok-tok Madagascar fody, Srin Class: Mammalia (Mammals)
Foudia sechellarum Foudia madagascariensis
Endemic Alien
Pteropus seychellensis
Night-time visitor to Cousine from mostly
Seychelles sunbird, Kolibri Family: Zosteropidae (White-eyes)
Order: Chiroptera (Bats) Family: Pteropidae (Fruit bats) Seychelles fruit-bat, Sousouri
Praslin Order: Cetacea (Whales and dolphins) Family: Delphinidae (Dolphins) Bottlenose dolphin, Marswen Spinner dolphin
Tursiops truncatus Stenella longirostris
Occasionally seen in pods off West coast Rare visitor to West coast
Megaptera novaeangline
Only three sightings in recent years
Suborder: Mysticeti (Whales) Family: Balaenopteridae Humpback whale
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SPECIES NOT INCLUDED IN THE CHECKLIST AND HAVE ONLY BEEN IDENTIFIED TO FAMILY Kingdom Monera; Division Cyanophyta (Blue-green algae); Family? One terrestrial species. Kingdom Plantae; Division Bryophyta; Class Musci (Mosses); Family? One terrestrial species. Kigdom Fungi; Class Ascomycota (Lichens); Families? At least three species. Kingdom Animalia (Animals); Phylum Platyhelminthes; Class Turbellaria (Free-living flatworms); Families? At least three terrestrial species; Class Cestoda (Tapeworms); Family? One species, from chicken; Phylum Aschelminthes; Class Nematoda (Roundworms); Family? One species from barn owl; Phylum Sipunculida (Peanut worms); Family Themistidae ? One species, a grey-tailed peanut worm; Phylum Arthropoda; Class Diplopoda (Millipedes); Family Geophilidae One species; Lithobiidae One species; Family Paradoxodomatidae (Keeled millipedes) One species; Family Polyxenidae (Pincushion millipedes) One species; Family? Three species; Class Symphyla (Symphylans); Family? One species; Class Entognatha; Order Diplura (Two-pronged bristletails); Family Japygidae One species; Order Collembola (Springtails); Family? 24 species; Class Insecta (Insects); Order Thysanura (Silver-fish or Fish-moths); Family? At least one species; Order Isoptera; Family? Order Blattodea; Family? Two species; Order Dermaptera (Earwigs); Family? Two species; One species; Order Orthoptera (Grasshoppers, cockroaches, mantids); Family Tettigoniidae (Bush crickets) Three species; Family Gryllidae (Crickets) Three species; Family Gryllacridoidea (Wingless long-horned grasshoppers) One species; Order Thysanura (Thrips); Family? One species; Order Coleoptera (Beetles); Family Carabidae (Ground beetles) Two species; Family Elateridae (Click beetles) One species; Family Eucmenidae (False click beetles) One species; Family Cerambycidae (Long-horn beetles) Two species; Tenebrionidae (Flour beetles) One species; Staphylinidae (Rove beetles) One species; Coccinellidae (Ladybirds) Four species; Family Curculionidae (Weevils) 17 species; Order Lepidoptera (Butterflies and moths); Family Nepticuloidea (Leaf-miner moths) At least one species; Family Geometridae (Loopers) One species; Lyonetiidae (Lyonet moths) One species; Gracillariidae (Leafminer moths) One species; (Order Hemiptera (Bugs); Family Anthocoridae (Minute pirate bugs) One species; Family Nabidae (Damsel bugs) One species; Family Lygaeidae (Seed bugs) 11 species; Order Homoptera (Cicadas, leafhoppers, scale insects); Cicadellidae (Leafhoppers) One species; Family Derbidae (Derbid planthoppers) One species; Family Delphacidae (Delphid planthoppers) One species; Family Ricanidae One species; Order Neuroptera (Antlions and lacewings); Family Chrysopidae (Lacewings) One species; Order Diptera (Flies) Suborder Nematocera (Long-horned flies); Family Tipulidae (Crane flies) One species; Family Tabanidae (Bloodsucking flies) One species; Family Dolichopodidae (Longlegged flies) One species; Suborder Brachycera (Short-horned flies); Family Phoridae (Humpback flies) One species; Family Pipuniculidae (Bigheaded flies) One species; Family Tephrididae (Picturewing flies) One species; Family Otitidae (Blackflies) One species; Family Platystomatidae (Metallic flies) One species; Family Neriidae (Slender flies) One species; Family Sepsidae (Ant flies) One species; Family Chamaemyidae (Aphid flies) One species; Family Lauxianiidae (Shade-flies) Two species; Family Chryomyidae ( Yellow flies) One species; Family Ephydridae (Shore flies) Three species; Family Drosophilidae (Small fruit flies ) Three species; Family Milichiidae (Long-nosed flies) Two species; Family Tethinidae (Tethinid flies) One species; Family Chloropidae (Triangle flies) Three species; Family Anthomyidae (Anthomyid flies) One species; Family Muscidae (House flies) Four species; Family Calliphoridae (Blowflies) Four species; Family Sarcophagidae (Flesh flies) One species; Family Hippoboscidae (Louse flies) One species; Order Hymenoptera; Suborder Apocritra; Family Diapriidae (Diaprid parasitic wasps) One species; Family Eucoilidae (Eucoilid parasitic wasps) One species; Family Chalcidae (Chalcid parasitic wasps) One species; Family Eulophidae (Eulophine parasitic wasps) One species; Family Vespidae (Paper and mason wasps) One species; Family Halictidae (Sweat bees) One species; Family Megachilidae (Leafcutter bees) One species; Family Anthophoridae (Carpenter bees) One species; Class Crustacea; Sub-class Cirripedia (Barnacles); Order Acrothoracica (Burrowing barnacles) One species; Sub-class Malacostraca; Order Isopoda (Isopods); Family? Two species, one terrestrial, one sea-shore species; Family Cymothidae Two species of fish parasites; Order Amphipoda (Amphipods); Families? Several marine species; Class Arachnida (Spiders, mites and ticks, and allies); Order Pseudoscorpionida (Pseudoscorpions); Family? Two species; Order Acari (Mites and ticks); Families? At least 36 species mostly in leaf litter; Order Aranaea (Spiders); Corinnidae (Dark sac spiders) two species; Lexoscelidae One species; Scytodidae (Spitting spiders) One species; Family? Six species; Phylum Echinodermata; Class Holothuroidea (Sea cucumbers); Family? At least two species; Class Ophiuroidea (Brittle stars); Family Ophiasteridae (Brittles stars) One species.
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GLOSSARY
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Adventitious (of roots) Afro-tropical
Small, secondary roots which often form a network
Alien Aplite Arborescent (of corals)
Not native to the area A fine-grained, light-coloured granite consisting almost entirely of quartz and feldspar Branching
Basalt
An igneous rock (coming from molten magma generated deep within the Earth’s crust) which is fine grained to glassy and low in silica content
Benthic Bleaching (of corals)
Living on the bottom of a sea or lake When exposed to high temperatures and high ultraviolet light levels corals turn white (bleach) through the loss of their colourful algal symbionts zooxanthellae
Brood-pouch Carapace (of crabs)
The pouch of an animal in which eggs or developing young are kept The central ‘shell’
Catastrophic regime shift cf
Such a major shift in ecosystem condition that it is radically and irreversibly changed A scientific convention where the identification is uncertain, and where a species appears like a particular, known species, but the exact idientity has no/cannot be determined
Chitinized
Describing structures made of chitin, a hard carbohydrate derivative forming the exoskeleton in arthropods (insects, spiders and other jointed animals)
Cloaca (of lizards) Coelenterates
The genital-urinary-intestinal opening animals in the Phylum Coelenterata, including sea anemones, corals, jellyfish and their kin. They Have a simple body plan, and have stinging cells (nematocysts) which they use to stun and capture
Coprophagous Crustose
prey Feeding on faeces Forming a crust-like growth
Detrital Disk (of echinoderms)
Small particles worn away from some solid body and in suspension in water The central area of the body
Dolorite Dyke
An igneous rock (coming from molten magma generated deep within the Earth’s crust) which is medium-grained and low in silica content A near vertical tabular intrusive body of rock
Ectoparasite Endemic
Parasite which lives on the outer surface of a host Occurring only in that area or region
Facilitation Feral Fringing reefs
Enhancement of the performance of one plant species by the close presence of another species Of a domestic animal surviving in the wild Coral reefs which fringe lan areas
Geniculate Granite
Bent abruptly at an angle An indigenous rock (coming from molten magma generated deep within the Earth’s crust) which is
Granitic islands
coarse Grained and high in silica content Islands formed of granite and part of the original landmass of Gondwanaland when Seychelles were joined to Africa, Madagascar, India, South America, Australasia and Antarctica
Hydromorphic (of soils) Inclusion Indigenous
Soils formed under damp or wet conditions Crystal, rock fragment or small bubble of gas, enclosed in a bigger crystal Occuring naturally
Interorbitally (of crabs)
Between the eyes
In or of Africa and the tropics
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Isopods Laterite
An order of small aquatic and terrestrial crustaceans A reddish rock material produced by weathering and occurring near the surface in tropical regions,
Molluscs
and usually high in oxides of iron and aluminium Snails, bivalves, octopii, squid, cuttlefishes and kin from the Arabic word ‘mawsim’ meaning ‘season’. Today it is applied to the type of wind system in
Monsoons Naturalised Nubbins
Heavily weathered granite boulders that develop horizontal partitions and giving the appearance of a pile of smaller boulders, which, in time, topple
Operculum Ovipositer Panicle
The bony plate covering the gills in bony fishes An extention at the end of an invertebrate's abdomen through which its eggs are laid A bunch of flowers (or seedheads)
Parapodium Phytophagous
One of the lateral foot-like locomotory staructures (parapodia) along the side of polychaete worms Plant-eating
Pioneers (of plants) Piscivores Planktonic
The first plants which establish themselves when habitat conditions change Fish-eating Small plants and animals drifting or floating in surface water
Plastron (of tortoises and turtles)
The ventral body shield
Platform reefs Pronotum Pterostigma
Coral reefs which are flat The dorsal part of the prothorax in insects A small, usually coloured, cell on the wingtip of some insects, iterally a wing-spot.
Pumice Pupa
Highly porous volcanic rock which floats in water Stage of development of some insects where the larva becomes encased in a hard shell
Reef front Reference (for restoration)
The seaward face of a reef A model for planning a restoration project, and later for its evaluation
Reference ecosystem Restoration (ecological)
An undisturbed area which can act as a reference, and model, for a restoration project The process os assisting the recovery of an ecosystem that has been degraded, damaged, or destroyed (Society for Ecological Restoration International Science & Policy Working Group 2004)
Rillenstein
Heavily weathered granitic boulders that have become vertically ribbed consolidated sedimentary rock made up of sand-sized grains, often with much quartz, cemented
Sandstone
Together with silica, clay minerals or carbonate describing small organisms, chiefly bacteria and fungi, which break down complex dead Protoplasm and release simple substances usable by plants
Saprophagic
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which there is a complete or near-complete reversal of prevailing direction from season to season with The ‘monsoons’ usually referring to the associated and periodic heavy monsoon rains. Alien plant that has established itself in the wild
Scandent (of plants)
describing plants which climb by leaning or hooking on to plants or other objects without the aid of twining or tendrils
Scutellum Shoal (in geology) Source habitat
A small shield-like, usually triangular, part of the dorsal covering of the body of some insects A platform of rock in shallow seas A localized area where populations of organisms show a net increase in number of individuals,
Spathe Stridulation
some of which may disperse outwards to neighbouring areas A large enveloping leaf, usually with a protective function The deliberate noise made by insects, usually to attract a mate and mostly done by rubbing two very
Surf zone
hard parts of the body together An area of breaking waves
Swash zone Sweep-netting Symbionts
The area where waves sweep onto the beach after breaking Catching invertebrates by sweeping a net through or above vegetation or other substrates Two types of organisms living in intimate contact with each other and both benefiting
Tarsi Tessellate Tibia Trade winds
A row of small joints making up the foot in insects Markings arranged in squares The slender part of the legs in insects which bear the tarsi Winds which blow from the sub-tropical belts of high pressure towards the equatorial region
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PHOTOGRAPHIC AND ARTWORK CREDITS (Numbers refer to page nos.; L = Left column; R = Right column; T = Top; C = Central; B = Bottom; ‘all’ refers to all illustrations on that page) Bourquin, Orty: 18LB; 29LT; 41LB; 46RC; 48LC,LB; 53RC; 56RT,RB; 60RC; 71LC; 75RC; 76RC; 80RC,RB; 81LT,LC,RC,RB; 82LC,RT; 83RC; 84LT; 85RC,RB; 86RB; 87LT,RT; 88LT; 88RC,RB; 89LB,RT; 90RT,RB; 92LT; 93LB,RT; 94RC; 95LB; 96LT,LB; 97RT; 100RB; 101RC; 111LT; 113LC; 116LB; 119RT; 120 all; 124LT; 126RC; 137LC; 138LT,LB; 139RT; 140 all; 141RC; 158LT,LB; 159LC. Cousine Island Trust: 4RB; 14RC; 74B. Friedli, Jean-Pierre: 13RT,RB; 14T. Gerlach, Justin: 112RB. Google Earth: 35LC; 65T. Hagens, Quetin: 81LB; 100LT; 174LC. Harvey, Martin: CoverC; viiB; xRB; 3RB; 30RC; 42RB. Henwood, Jock: 23LT,LC; 37RT,RB; 39RT,RC,RB; 83LC; 86RC; 87LC,RB; 88RT; 111RT; 118LC; 119RC; 121RB; 133LB; 156LC; 171 all. Hitchins, Peter: viiiB; 4LB; 6RB; 11LC; 12 all; 13LT; 14RC; 15LT,LB; 16T,LB,RB; 17RT,RB; 18LC,RC; 19LC,RT,RB; 20RT,RB; 21T; 22T,RB; 23RT,RB; 25T; 26T; 27LB,RT; 28RT,RC; 29LB,RC,RB; 30LT,LC; 31LB,RT,RC; 32LT; 33LT,LC,LB, RT,RC,RB; 35RT,RB; 41LC; 42LT; 43RT,RB; 44RC; 45LT,LC,RB; 46LT,RT; 47LT,RT,RC,RB; 48RC; 49LT,LC,RT,RC,RB; 50LC,LB,RT,RB; 51LT,LB,RC,RB; 52 all; 53 all; 54LT,RT; 55LT,RT; 61LT; 63LT,LC; 65RC; 66 all; 67 all; 68 all; 69 all; 70 all; 71 all; 73 all; 74LT,RT; 77RB; 80LC; 83RT; 84RT; 90LC; 91LC,LB; 92LB,RT,RC,RB; 93LT,RC,RB; 94LB,RB; 95RB; 98LB,RC,RB; 100LT,LB; 101LB; 106RB; 108RB; 110RC; 114RT; 118RC,RB; 125RB; 126LB; 127RC; 128 all; 129 all; 130 all; 131 all; 132 all; 133LT,LC; 134B; 135 all;136 all; 137LB,RT,RC,RB; 138LT,LB,RT; 139LT,LC,RC; 141LT,LB; 142 all; 143 all; 144 all; 145LT,RT,RC; 147 all; 148RT,RC; 149 all; 150 all; 151LT,LC,LB; 152RT,RC,RB; 153 all; 154 all; 155 all; 156LT(1)LT(2),LB,RT,RC,RB; 157 all; 158RC,RB; 159LT,LB,RT,RC,RB; 160LT,LB,RB; 161 all; 162LC,LB,RB; 163 all; 164 all; 165 all; 166 all;167 all; 168 all; 170LC,LB,RT; 172 all; 173 all; 174RT,RB; 175 all; 176 all; 177 all. Hitchins, Stella: 151RB; 152LT; 169 all. Jolliffe, Kevin: 76LT; 170LB. Lawrence, James: 117B; 146LT. Leslie, Bruce: 94LT; 148LC. Rocha, Sara: 145LC. Samways, Melinda: 39LB; 79RB; 121RT; 122 all; 124LB,LC. Samways, Michael: ixRB; xiRB; xiiB; 10RT; 17LB; 18LT; 27RC; 28RT,RC; 31RB; 36LB,RT,RC,RB; 38LT,LB,RC; 39LT; 40LT,LB,RT,RB; 41RT; 42LC; 44LT; 47LC; 61B; 76LC,LB; 77LT,LC,LB,RT,RC; 78 all; 79LT,LB,RT,RC; 83LT; 85LT; 101LC; 102LB,RC; 103 all; 104 all; 105LC,RT; 106LT,RB; 107RT,RB; 108LT,RT; 109 all; 112LT,LB; 113RC; 114LT,LB; 115 all; 116RT. Seychelles Government: 10B. Van Eck, Karl: 37LB; 75LB. Vrdoljak, Sven: 2T; 5B; 24T; 25B; 30B; 32B; 34B; 72T. About the authors: Michael Samways is Professor and Chair of the Department of Conservation Ecology and Entomology, Stellenbosch University, South Africa. Peter Hitchins was Cousine Island Manager 1995-2001, and Conservation Advisor to the Island 2002-2004. Orty Bourquin was Conservation Consultant to Cousine Island during instigation of the Island’s Management Plan. Jock Henwood has been Cousine Island Manager, 2002-present.
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INDEX
Abalistes stellatus 123 Abudefduf spp. 126 Abutilon indicum 53 Acalypha indica 52 Acanthopleura cf gemmata Acanthurus leucosternon 121 Acanthurus triostegus 121, 126 Acanthurus xanthopterus 121, 126 Achaea catella 112 Achatina fulica 97 Achatina shell 91 Achyranthus aspera 46, 48, 68 Acridotheres tristis 175 Acrocephalus sechellensis 169-170 Acropora austera 75, 78, 84 Acropora clathrata 36, 37 Acropora formosa 36, 40, 76-78 Acropora gemmifera 78 Acropora robusta 40, 76-77 Acrostichum aureum 44 Actinopyga mauritiana 86-87 Adoretes versutus 109 Aedes unilineatus 110 Aerial view of Cousine, 1960 74 Aerial view of Cousine 2007 74 Aetobatus narinari 119 African grass blue 111 African monarch 111 Afrotropical carpenter bee 113 Agrius convolvuli 112 Ailoronyx seychellensis 140-141 Albinism, in turtles 133 Aldabrachelys gigantea 135-138 Aldabran snail 97 Aldabran tortoises 135-138 Alexandrian laurel 43 Alexandrian laurel, seeds 17 Alien birds 17, 174-176 Alien invasives 3 Alien plant removal of 62-70 Alien plant species, number eradicated 15 Alien plant species, number of 15 Alien snail 97 Allochthonous inputs 1 Alluaud’s potter wasp 113 Alluaud’s spider cricket 105 Alocasia macrorrhiza 54 Alpheus sp. 86 Alternanthera sessilis 54 Amaranthus 111 Amaranthus dubius 46,52 Amberwing emperor 102 Amblyomma loculosum 99-100 American cockroach 106 Amitie 64
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Amphipods 85 Amphiprion akallopisos 79 Amphiprion fuscocaudatus 79 Anampses meleagrides 123 Anax ephippiger 102 Anemone disappearance, and great bleaching event 79 Anemone fish 79 Anemone fish loss, and great bleaching event 79 Anemones 79 Angelfishes 121-122 Anoplolepis gracilipes 19, 117 Anous stolidus 153-155 Anous tenuirostris 152-153 Anthus trivialis 174 Antlions 108 Ants 19-20, 114-117 Ants, and cottony cushion scale 107 Ants, and Pulvinaria scale 107 Apanteles sp. 112 Apartments 13 Aphid 107 Apis unicolor 113-114 Aplysia dactylomela 42 Apogon cookii 124 Aprion virescens 125 Apus affinis 174 Arabian cowrie 80 Arctic skua 161 Ardea cinerea 162 Arenaria interpres 164 Aretopsis amabilis 86, 90 Argusia argenta 64 Aride Island 17, 19, 42, 43, 55, 63, 64, 67, 100, 132, 139, 141, 144, 172, 178 Arrhinotermes calanifrons 166 Arthritic spider conch 80-81 Asian lesser cuckoo 174 Atergatis subdentatus 96 Audubon's shearwater 148 Auger 81 Austromegabalanus sp. 84 Avocado 45 Aystasia gangetica 44, 48, 49, 52, 54 Balanus sp. 84 Balfour's pandanus 43, 59-61 Bamboo 66-67 Bambusa vulgaris 66-67 Banana 45 Banded limpet 81 Banded zebra shrimp 86 Banded-club urchin 89 Bankia 83 Bar-cheek trevally 120 Barn owl 18, 174 Barnacles 84-85 Barracuda 120 Barred flagtail 126
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Barred ground dove 17, 174 Barringtonia asiatica 67 Bartailed godwit 164 Baseline study 63 Bathygobius sp. 42 Beach crest 32 Beach dynamics 30-34 Beach instability 23 Beach lagoon 41-42 Beach morning glory 33, 43, 44, 45, 57 Beach pool 41-42 Beach profile 34 Beach sand erosion 29 Beach sand volume 32 Beach width 30-35 Beach, seeds on 17 Beaching seed 64 Bedrock 27-29 Bees 113-114 Beetles 108-109 Bicolor cleaner wrasse 123 Bigeye trevally 120 Big-headed ant 107, 108, 114-115 Big-headed ant, and ladybirds 109 Bird Island 64, 141 Birds of prey 174 Birgus latro 6 Bivalves 82-83 Black kite 174 Black louse fly 110-111 Black needle urchin 88 Black pearl oyster 82 Black ponerine ant 114 Black sea cucumber 87 Black snouted termite 106 Black triggerfish 123 Blackback butterflyfish 122 Blackbanded cardinalfish 124 Blackfin barracuda 120 Black-naped tern 161 Black-scaled chiton 80 Blackspot emperor 126 Black-spot snapper 125 Blackspotted rockskipper 126 Blasting 13 Bleaching event, and clams 82 Bleaching of corals 36-39, 75-78, 126 Blue percher 103-104 Blue-eyed hermit crab 91 Bluefin trevally 120 Blue-green sedge 46, 51, 54 Blue-legged centipede 101 Blue-lined large-eye bream 124 Bluespotted ribbontail ray 119 Bluestreak cleaner wrasse 123 Boerhavia repens 45, 46, 52, 68 Bolbometopon muricatum 122
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Borbo borbonica 112 Bottlenose dolphin 178 Boulders 27-29 Brachiaria 51 Brachiaria subquadripara 51 Braconid wasps 112 Branched murex 80-81 Breadfruit 45 Breeding, of turtles 127-134 Bridled tern 42, 160 Bridled triggerfish 123 Brittle stars 88 Brittleworms 84 Broad-leaf steno 45 Broadleaf steno 46, 47 Bronze gecko 140-141, 144 Broom earthworm 97 Brooms 12 Brown noddies, in coconut palms 16 Brown noddy 63, 153-155 Brown rat 178 Bubulcus ibis 162 Bugs 107 Bumphead parrotfish 122 Butorides striatus 162 Butterflies 111-112 Butterflies, and reduced habitat 111 Butterflyfishes 122 Caecilians 127 Caenobita sp. 90 Caerulean damsel 121 Caladris minuta 164 Calcinus laevimanus 42, 91 Calidris ferruginea 164 Calidris temmincki 164 Calophyllum inophyllum 43, 66 Calotermes scotti 106 Calotomus carolinus 126 Canavalia cathartica 53 Candycane longface wrasse 123 Capilius maculatus 96 Carangoides fulvoguttatus 120 Caranx ignobilis 120 Caranx melampygus 120 Caranx plagiotaenia 120 Caranx sexfasciatus 120 Carcharhinus amblyrhynchos 119 Cardinal 175-176 Cardisoma carniflex 96 Caretta caretta 134 Carnelian cowrie 80 Carpenter bees 113 Casuarina 57, 65 Casuarina logs, and millipedes 101 Casuarina, and ground cover 70 Casuarina, logs for protection of seedlings 66 Casuarina, planting of 12
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Casuarina, removal of 57, 68-70 Casuarinas, formerly along beach 42 Cat predation 14 Catastrophic regime shift 1, 62 Catharanthus roseus 46, 47, 48, 52 Cats 178 Cats, eradication of 14 Cattle 178 Cattle egret 162 Cave 28 Cellana livescens 81 Centipedes 101-102 Cephalopholis agrus 125 Cephalopholis mimiata 125 Cerf Island 141 Ceriagrion glabrum 102 Chafers 108 Chanos chanos 41, 42 Charadrius hiaticula 164 Charybdis sp. 95 Cheilinus trilobatus 123, 126 Cheilodipterus artus 124 Chelonia mydas 127-130, 133 Chickens 14 Chicoreus lambis 80-81 Chilocorus nigritus 109 Chiton sp. 80 Chitons 80 Chlaenius bisignatus 108 Chlorodesmis 41 Chrysiptera spp. 126 Chthalamus sp. 84-85 Ciguatoxins 125 Citrus 45 Clams 82-83 Cleaner shrimps 86 Cleaner wrasses 123, 124 Clibanarius virescens 91 Climate change 31 Clinopogon nicobarensis 110 Coast cordia 43 Coast grass 43, 44, 48, 49, 51, 68 Coast grassland 46 Coastal plain 44, 62 Coastal plain, prior to restoration 63 Coastal plain, restoration of 67-68 Cockroaches 105-106 Coconut harvesting 16 Coconut palm 10, 54, 55, 56, 57, 63 Coconut palm seedlings 54 Coconut palm, clearing of 55 Coconut plantation 13 Coconut tree removal 15, 26 Coconut trunk damage 108 Coconuts, for seedling protection 65 Coenobita brevimanus 91 Coenobita perlatus 91
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Coenobita rugosus 91 Coetivy Island 141 Colobocentrorus atratus 89 Comb grass 43, 46, 47, 48, 51 Common citril 102 Common diadem 111 Common ringed plover 164 Common ruspolia 104 Common star 87 Common tern 161 Compressed sedge 51, 54 Conceptual model, of restoration 2 Conch shells 80, 81 Conservation programme, initiation 15 Contamination risk 20 Continental glider 103 Conus aulicus 81 Conus geographus 81 Conus shell 90 Convinct surgeonfish 121, 126 Convolvulus hawk 112 Copra 12 Copsychus sechellarum 166-169 Coral bleaching 4, 36-39, 75-78, 126 Coral colonization 37 Coral hind 125 Coral nurseries 37 Coral rabbitfish 121 Coral rubble 28, 38 Coral trade 18 Corals 75-79 Cordia subcordata 43 Cornetfish 120 Coromandel 11, 44, 48, 49, 52, 54, 60, 66-67, 111 Coromandel herbland 49 Coscinaraea sp. 75 Cotton 53 Cotton fibres, for nests 53 Cousin Island 19, 25, 43, 55, 63, 100, 127-132, 133, 139, 141, 144, 172, 174, 177, 178 Cousine Island, 1960 74 Cousine Island, 2007 74 Cousine, and Seychellois 11 Cousine, conservation significance 7-9 Cousine, early history 10-11 Cousine, grid reference 7 Cousine, in 1960s 1, 10-11 Cousine, size 7 Cousinea 98 Cowries 80 Cows 14, 178 Crab plover 164 Crabs 92-96 Crabs, feeding on millipede 100 Cracker shrimp 86 Crazy ant 19, 117 Crenimugil crenilabris 126
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Crenimugil crenilatrus 121 Crescent-banded grunter 42 Crickets 104-105 Crocodylus porosus 6 Crop plants 64 Crustaceans 84-86 Cuckoos 174 Cuculus canorus 174 Cuculus poliocephalus 174 Cultivated plants 15, 45 Cultural elements, and restoration 62 Curieuse Island 139,141 Curlew 164 Curlew sandpiper 164 Currents, of oceans 35 Custard apple 45 Cyclones 22 Cynodon dactylon 45 Cyperus compressus 51 Cypesus conglomeratus 51 Cypraea arabica 80 Cypraea caputserpensis 80 Cypraea carneola 80 Cypraea diluculum 80 Cypraea helvola 80 Cypraea moneta 80 Cypraea talpa 80 Cypraea tigris 80 D' Arros Island 139, 172 Dactylobolus bivirgatus 101 Dactyloctenium ctenoides 43, 46, 47, 48 Damania anjouana 126 Damselflies 102 Damselfishes 126 Danaus chrysippus 111 Dardanus sanguindentus 90 Dardanus shrimps 90 Dardanus sp. 86 Dardanusmegistos 90-91 Dark ghost crab 57, 94 Dark green warted sea cucumber 87 Darting green cricket 104 Datura metel 46 Dawn cowries 80 Decorator crabs 96 Defaecation, and seed dispersal 19 Delphacid homopteran 108 Denis Island 139-141, 172, 178 Dermochelys coriacea 134 Desjardin's sailfin tang 121 Development, limitation 26 Diadem butterfly 23, 111 Diadema savignyi 88 Dichogaster affinis 97 Digitaria spp. 49 Diplacodes trivialis 103-104
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Diploastrea heliopora 75-76, 79 Dogs 178 Dogs, formerly on Cousine 11 Dolphins 178 Double-lined mackerel 120 Dragonflies 102-104 Drexelia bifida 99 Drift line 63 Driftline, seeds 17 Dromas ardeola 164 Drought 21-22 Dry periods 21-24 Dugong 6 Dugong dugong 6 Dune crest 17, 32, 33, 34, 63, 64-65 Dune crest erosion 42 Dune, undermining of 32-34 Dusky sweetlips 126 Dusky wrasse 126 Dussumier's rockskipper 126 Dwarf hunting spiders 99 Dykes 27 Dysmicoccus sp. 114 Earth centipedes 101 Earthworms 97 Earwigs 105 Easter Island 1 Eastern little tuna 120 Echeneis naucrates 121 Echidna nebulosa 119 Echinochalina sp. 75 Echinometra mathaei 89 Echinopora gemmacea 76-79 Echinopora lamellosa 75 Echinothrix calamaris 88 Ecological integrity 2-3, 62 Ecological landscaping 3 Ecological restoration, principles 62 Ecological trajectories 62 Ecosystem function 62 Ecosystem restoration triage 2 Ecotourism 20 Egrets 162 Ehinephelis spilotoceps 125 Electrocution, of fruit bats 177 Eleonora's falcon 174 Elongate giant clam 82 Emperor angelfish 121 Emperors 124 Endemic trees, introduced 17 Enneapterygius elegans 126 Enteropogon seychellensis 43, 44, 48, 49, 51 Entomacrodus striatus 126 Entreating cricket 104 Ephinephelis tukula 125 Epinephelis caeruleopunctata 125 Epiphytes, absence of 54
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Eragrostis tenella 51 Eretmochelys imbricata 127-134 Eriphia laevimanus 95 Erosion, of beaches 27, 30-34 Euborellia annulipes 105 Eucidaris metularia 89 Eudrilus eugeniae 97 Eumeues alluaudi 113 Eunice sp. 84 Euphorbia 111 Eurphorbia hirta 52 Euphorbia prostrate 45 Euphorbia pyrifolia 43, 44, 47 European cuckoo 174 European earwig 105 European golden oriole 174 European swallow 174 Euthynnus affinis 120 Extinction crisis 1 Extinction of experience 64,147 Extinction of experience, rescuing 6 Extinction, of Mascarene fruit bats 177 Extinction, of Red achatina 97 Extinction, of swamp grass 17 Eyed ground beetle 108 Eyed star 87 Eyed coral crab 96 Fairy tern (see White tern) Falco eleonora 174 Falco subbuteo 174 Falco vespertinus 174 False limpet 81 Feathery sedge 51 Félicité Island 100, 139 Feral cats 14 Fern 54, 56, 60 Ficus lutea 54 Ficus reflexa 43, 53, 54 Ficus spp. 43, 44, 66 Ficus-Pisonia forest, and centipedes 101 Fig forest 54-55 Fig trees, and cottony cushion scale 107 Fig-Euphorbia woodland 53-54 Fig-Pisonia forest 55 Figs, establishment 66 Figs, as fodder 15 Figs, pollination 112 Fimbristylis cymosa 51 Fine steno 43, 53 Finger grasses 49, 51 Fireleaf 43, 44, 47, 53, 55, 60 Fish traps 18 Fishes 118-126 Fishing 12 Fish-kill tree 67 Fistularia commersonii 120 Five-leaf morning glory 43, 48, 55, 56
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Flagtail 42 Flat-bellied ground spiders 99 Flatties 99 Fleshy portulaca 43, 46, 48, 52, 111 Flies 110 Flooded tracks 69 Floods 22 Flower scarab 109 Flower-pot snake 145 Flying fish 35 Fodies 172-173,175-176 Forest panicum 54 Forktail rabbitfish 121 Fossils 29-30 Foudia madagascariensis 175-176 Foudia sechellarum 172-173 Foursaddle grouper 125 Foxtail 51 Fregata ariel 151 Fregata minor 151-152 Frégate Island 43, 100, 141, 144, 172, 178 Friedl, J.-P. 13 Frigate birds 151-152 Fringelip mullet 121, 126 Fringing reef 39 Frogs 127 Fruit bat 9, 63, 177 Fruit bats, as human food 19 Fruit bats, in captivity 19 Fruit trees 15 Fungi 72-73 Fungia scutaria 76 Fungia spp. 75 Fused coral rubble 38 Galeocerdo cuvier 118 Gallinula chloropus 162-163 Garbage disposal 15 Garbage, causing death 20 Gardiner's skink 145 Geckos 139-142 Geochelidon nilotica 161 Geographer cone 93 Geographus crinipes 93 Geographus stormii 93 Geology 27-29 Geometric moray 119 Geopelia striata 174 Geyhra mutilata 141 Giant clams 82-83 Giant millipede 100-101 Giant millipede segments, and skinks 143-144 Giant moray 119 Giant plated barnacle 84 Giant tortoise, and seed dispersal 64 Giant tortoise, grazing by 51 Giant tortoises 135-138 Giant tortoises, and impact on seedlings 66
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Giant trevally 120 Giant triton 18 Gnathanodon speciosus 120 Gnathophyllum sp. 86 Goatfishes 123 Goats 178 Gobies 42 Goldbar wrasse 126 Golden trevally 120 Gomphosus coeruleus 123 Gondwanaland 6 Gonodactylus sp. 85 Goose barnacle 84 Gorgeous hermit crab 91 Gossypium hirsutum 53 Grammatorcynus bilineatus 120 Grand Soeur Island 141 Granite boulders, in sea 38, 41 Granites 27-28 Granular brittle star 88 Grapsus tenuicrustatus 92-93 Grasshoppers 104 Grasslands 46-47 Grazing 49 Great bleaching event 36, 126 Great bleaching event, and clams 82 Great hammerhead shark 119 Greater frigate bird 151-152 Greater sandplover 164 Greater-crested tern 161 Green jobfish 125 Green mantis shrimp 85 Green shield bug 107 Green turtle 127-130, 133 Greenbacked heron 162 Greenhead sedge 51 Grenadilla 64 Grey bump coral crab 96 Grey heron 162 Grey plover Grey reef shark 119 Ground cover 54,55,56,57, 60 Groupers 125 Gryllodes supplicans 104 Guava 64 Guettardia 64, 67 Guettardia speciosa 64, 67 Guides, to wildlife 5 Guinea grass 12, 54 Gull-billed tern 161 Gygis alba 155-160 Gymnocranius grandoculis 124 Gymnothorax javanicus 119 Hairy chiton 80 Hairy euphorbia 52 Halfbeak 119 Half-flower 43, 50-51
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Half-flower shrubland 33 Half-flower, replanting of 50-51 Halochoeres marginatus 126 Hammer mill 65-66 Hammerhead 119 Hand removal, of alien plants 64 Harvesting, of sea birds 11-12 Hawksbill turtle 19, 75-81,127-134 Hawksbill turtle egg, crab attack on 94 Hawksbill turtle nest 23 Hawksbill turtle, shark attack on 118 Herbicides, avoidance of 62 Herblands 48-49 Herbs 45 Heritiera littoralis 66 Hermit crabs 90-92 Hermit crabs, and snapping shrimps 86 Hernandia nymphaeifolia 64, 67 Herons 162 Heteractis magnifica 79 Heterocentrotus sp. 88 Heteropoda venatoria 99 Hexabranchus sanguineus 82 Hibiscus shrubland 50 Hibiscus tiliaceus 43, 50 Hill summit 26 Hirundo rustica 174 Historic compostion 63 Historic condition, restoration of 62 Hobby 174 Hologymnosus doliatus 123 Holothuria atra 87 Honey buzzard 174 Honey cowrie 80 Honeybee 113-114 Honeydew 107 Honeydew excretion 115 Horn-eyed ghost crab 93-94 Horses 178 Houndfish 119-120 Hourglass triplefin 126 House daddy-longleg 99 House mouse 178 Humidity 21 Humpback snapper 125 Humpback whale 178 Hunting crab spider 99 Hybridization, turtle dove 165-166 Hydromorphic soils 54 Hypolimnas misippus 23, 111 Hyporhamphus affinis 42, 119 Icerya seychellarum 107 Ichneumon wasps 112 Imbricate pearl oyster 82 Indian abutilon 53 Indian acalypha 52
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Indian cockroach 105-106, 168 Indian mulberry 44, 53, 54, 55 ,57 ,60, 67 Indian mynah 17, 175 Indian Ocean bird wrasse 123 Indigenous plants, propagation of 63 Indigenous trees 17 Infrastructure 20, 25 Insects 102-117 Insular halfbeak 119 Intertidal zone 41-42 Inter-tidal zone fishes 126 Invertebrates, and restoration 63, 69, 97 Ipomoea macrantha 47, 53 Ipomoea pescaprae 33, 43, 44, 45, 46,48, 49 Ipomoea venosa 43, 48 Irrigation 64-65 Island fern 43-44, 54, 56 Isopods, marine 85 Isopods, land 117 Istiblennius dussumieri 126 Istiblennius edentulous 126 Istiblennius gibbifrons 126 Jamaican vervaine 47, 52 Jasomenia sansibara 104 Jewelry manufacture, from turtles 12 Jumping spiders 99 Kare 12 Keeled millipedes 101 Keystone species, ant 116 Killifish 110 Kleptoparasites 98 Krakatau 63 Krill 35 Kuhlia mugil 42, 126 Kyllinga polyphylla 51 La Digue Island 100, 133, 139, 141, 177 Labia minor 105 Laboudallon, V. 14 Labroids bicolor 123 Labroids dimidiatus 123 Lactoria fornasini 123 Lambis chiragra arthritica 80-81 Lambis crocata 80 Lampides boeticus 111 Lamycetes sp. 101 Land hermit crabs 91-92 Land snails 97 Landscapes of Cousine 25-26 Large spotted coral crab 96 Large-leaf fig 55 Large-leaf morning glory 47, 53 Large-spotted coral crab 96 Lawns 45 Leaf litter 55-56, 69-70,101 Leaf litter, and cockroaches 105 Leatherback turtle 134
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Leeches 97 Lepturus radicans 51 Lepturus repens 51 Lerop koko 16 Lesser frigate bird 151 Lesser noddy 68, 70, 152-153 Lesser noddy mortality 153 Lesser noddy, and Pisonia 57-59, 153 Lesser noddy, trapped by Pisonia seeds 59 Lesser-crested tern 161 Lessy noddy, nesting season 23 Lethrinus mahsena 124 Lethrinus nebulosus 124 Lethrinus variegatus 124 Lethriunus harak 126 Lianas, lack of 54 Limestone intrusion 28 Limosa leschenaultia 164 Limosa limosa 164 Limpets 81 Linckia laevigata 87 Lined cardinalfish 124 Litter spiders 99 Litter standing crop 100 Littering 20 Little crazy ant 116 Little orb spider 99 Little sticky seed 45, 46, 52, 68 Little stint 164 Little swift 174 Little ubiquitous brown ant 117 Littoraria glabrata 82 Livestock 178 Lizards, endemism in Seychelles 8 Lobophyllia hemprichii 78 Lobsters 85 Local extinctions 62 Log earthworm 97 Loggerhead turtle 134 Logs and earthworms 97 Logs, and fungi 72-73 Loimia medusa 84 Loligo sp. 83 Longfin spadefish 125 Longfruit phyllanthus 45 Long-horned decorator crab 96 Long-jawed squirrelfish 123 Long-legged spiny lobster 85 Long-spike lepturus 51 Long-stripe millipede 101 Looking-glass tree 66 \Looking-glass tree, seeds 17 Louseflies 110 Love grass 51 Lucerne blue 111 Lutjanus bohar 125 Lutjanus fulviflammus 125
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Lutjanus gibbus 125 Lycognathophis seychellensis 145 Mabuya seychellensis 142-143 Mabuya wrightii 144-145 Madagascar fody 17, 175 Madagascar fody, trapped by seeds 53 Madagascar periwinkle 46, 47, 48, 52 Magnificent sea anemone 79 Magpie robin (see also Seychelles magpie robin)166-169 Mahé highlands 21 Mahé Island 43, 97, 133, 135, 141, 177, 178 Maned rockskipper 126 Mango 45 Mangrove crab 96 Mantis shrimps 85 Mapou 10 Marianna Island 139 Marine worms 84 Mariscus dubius 44 Mariscus ligularis 46, 109 Mason wasps 113 Mass bleaching of corals 36, 126 Mealybug 114 Mecistocephalus spp 101 Medusa tangleworm 84 Megaptera novaeangliae 178 Melichthys niger 123 Merten's sea anemone 79 Mice 19-20, 178 Midget ground weavers 99 Milk shark 119 Milkfish 41, 42 Millipede restoration 101 Millipedes 100-101 Milvus migrans 174 Mission Statement 15 Mites 99 Mole cowrie 80 Money cowrie 80 Money spiders 99 Monitoring 64 Mono 125 Monodactylus argenteus 125 Monsoons 22-24, 65 Monsoons, and sand 30-34 Monsoons, and sea temperatures 35 Montipora digitata 78 Moorhen 162-163 Moorhen, and seed dispersal 64 Moorhen, crab attack on 93 Moorhen, predation on skinks 142 Moorish idol 121-122,124 Moray 119 Morinda 107 Morinda citrifolia 44, 67 Mosquitoes 110 Motacilla alba 174
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Motacilla flava 174 Moths 111,112 Mown lawns 45 Mullets 120-121 Mulloidichthys flavolineatus 123 Murex 80 Mus musculus 178 Mushroom corals 75 Mynah 17, 175 Myripristis seychellensis 124 Myrmeleon obscurus 108 Naso brevirostris 121 Naso lituratus 121 Nasutitermes nigritus 166 Natural capital 62 Neavella albipectus 110 Nectarina dussumieri 172 Neoferdina offreti 87 Nephila inaurata 98 Nephrolepis biserrata 43-44 Nesogeophilus leptocilus 101 Nezara viridula 107 Nightshade 54 North hill 26-27, 62, 63 North Island 141, 178 North point 49 Nubbins 27 Numenius arquata 164 Numenius phaeopus 164 Ocean currents 35 Ochrosia 67 Ochrosia oppositifolia 63, 67 Octopus 83 Octopuses 83-84 Ocypode ceratophthalumus 93-94 Ocypode cordimana 94 Ocypode ryderi 94 Odontomachus troglodytes 114 Odynerus seychellensis 113 Oil, on beach 1 Olive-haired skipper 112 Ophiocoma scolopendrina 88 Orange spider conch 80 Orangespine unicornfish 121 Organ pipe coral 75-76 Oriental sweetlips 124. 126 Oriolus oriolus 174 Ornamental plants 15 Orthetrum stemmale wrightii 103 Oryctes monoceros 108 Otaheite gooseberry 45, 54 Otostigmus rugulosus 101 Oval black urchin 89 Oysters 82 Pachypanchax playfairi 110 Pacific almond 54, 66-67 Pacific almond forest 54
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Pacific almond, seeds 17, 19 Pacific gecko 141 Pacific golden plover 164 Padina 40 Painted lady 111 Painted spiny lobsters 85 Palinurus longipes 85 Palinurus penicullatus 85 Palinurus versicolor 85 Palm spider 98 Palolo-worm 84 Pamelaescinus gardineri 145 Pandanus balfourii 43, 59-61 Pandanus forest 59-61 Panicle, of Pisonia 58 Panicum maximum 54 Pantala flavescens 102-103 Papaya 15, 45 Papaya escapee 46 Papaya, dispersal 45, 64 Papilla 87 Paratrechina longicornis 116 Parupeneus cylostomus 123 Paspalidium geminatum 17, 54 Passiflora foetida 46 Patella pica 81 Pavona clavus 39, 76-78 Peacock grouper 125 Pear oysters 82 Pearly hermit crab 91 Pedilanthus tithymaloides 15 Pelamis platurus 127, 145-146 Penaeus caniliculatus 42, 86 Pennisetum polystachyon 51 Periplaneta americana 106 Periwinkle 46, 47, 48, 52, 82 Pernis apivorus 174 Petit Soeur Island 139 Phaeton lepturus 148 Phaeton rubricauda 151 Pheidole megacephala 114 Phelsuma astriata 139 Phosphatic sandstones 28-29 Phrynichus scaber 98 Phyllanthus 45 Phyllanthus pervilleanus 47, 83 Picture rockskipper 126 Pigeon 165 Pigs 14, 178 Pigweed 46, 52, 63 Piket koko 16 Pinctada imbricata 82 Pinctada nigra 82 Pink ghost crab 94 Pink swimming crab 95 Pink-striped barnacle 84 Pirogues 11, 13
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Pisonia 43, 67 Pisonia and sea birds 57-59 Pisonia flowerhead 58 Pisonia forest 54, 55-59 Pisonia forest, and ants 114-116 Pisonia forest, and pseudoscorpions 98 Pisonia grandis 10, 15, 43, 67 Pisonia seedlings, under Casuarina 57 Pisonia, and fody entanglement 176 Pisonia, and Pulvinaria scale 107 Pisonia, and scale insects 114-115 Pisonia, as fodder 15 Pisonia, breakage 56 Pisonia, effects of salt spray on 47 Pisonia, establishment 71 Pisonia, regeneration 56 Pisonia, seedlings 68, 70 Plant colonizers 44 Planting out 65 Planting, of indigenous plants 64 Playfair's panchax 110 Plectoglyphidodon spp. 126 Plectorhinchus chubbi 126 Plectorhinchus orientalis 124, 126 Plovers 164 Pluvialis fulva 164 Pluvialis squatarola 164 Poaching 3, 13, 62 Pocillopora damicornis 78 Pocillopora eydouxi 37, 39, 75, 77, 78 Poisnous cones 81 Poisnous crab 95-96 Poisnous fishes 125 Poisnous snake 127 Poison apple 46, 52, 57 Poisoning, by spines 119 Poisonous spiders 99 Polar Star Company 11-13 Polistes olivaceus 112 Polydactylus sexfiles 120 Pomacanthus imperator 121 Pomocentrus caeruleus 121 Pomocentrus suphureus 121 Pompano 40 Pontoscolex corethrurus 97 Pool, on beach 41-42 Porcupine ray 119 Porites 37 Porites lutea 78 Porites solida 39 Portulaca oleracea 43, 46, 47, 48, 49 Potato grouper 125 Poultry 14 Powder-blue surgeonfish 121 Praslin 64 Praslin Island 17, 18, 43, 64,97, 133, 135, 139, 141, 162, 163, 174, 177, 178
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Prawn, striped 42 Prawns 86 Precautionary conservation 67 Pretty poison crab 95-96 Prickly pear 15 Pronghorn spiny lobster 85 Propagation, of indigenous plants 64 Prostate euphorbia 45, 52 Protaetia aurichalcea 109 Protea urchin 89 Protective logs, for seedlings 66 Pseudoscorpions 98 Pteronemobius 104 Pteropus seychellensis 63, 177 Puffinus lherminieri 148 Puffinus pacificus 147-148 Pulvinaria scale 114-115, 167 Purple-banded hermit crab 91 Pycnoscelus indicus 105-106, 168 Pycreus polystachyos 51 Quarantine 20, 64 Rabbitfishes 121, 126 Racoon butterflyfish 122 Radula 81 Rainfall, annual 21-24 Rainfall, monthly averages 24 Ramhotyphlops braminus 145 Rat-control protocol 12 Rats 19-20, 178 Rattus norvegicus 178 Rayed limpet 81 Rays 119 Récif Island 43 Recovery principles 1-3, 62-63 Recovery, philosophy 62-63 Red achatina 97 Red achatina, extinction of 21-22 Red hermit crab 90-91 Red List 19 Red-and-white urchin 88 Red-eyed coral crab 95 Redfin butterflyfish 122 Red-footed kestrel 174 Red-legged centipede 101 Redlip parrotfish 126 Red-spot swimming crab 94 Red-tailed tropicbird 151 Reef damage 18 Reef whitetip shark 119 Reference surveys 63 Reference-based forest 63 Regime shift 62 Relative humidity 21 Remnant natural capital 62 Removal, livestock and cats 3 Research policy 20 Restoration progression 72
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Restoration, and millipedes 101 Restoration, phases of 63 Restoration, philosophy 62-63 Restoration, principles 1-3, 62-63 Restoration, south of pavilion 69 Rhachistia aldabrae 97 Rhincodon typhus 118 Rhinecanthus rectangulus 123 Rhinoceros beetle 108 Rhisotrogus 109 Rhombic triumfetta 53 Rhyzoprionodon acutus 119 Ridge and groove geology 27-29 Rillenstein 27 Ringed sea hare 42 Ringlegged earwig 105 Rippled rockskipper 126 Rise, in sea level 31 Rivulated rabbitfish 121 Roads 69 Robber crab 6 Robber flies 110 Rock crab 92-93 Rock formations 27-29 Rockskippers 126 Roosting, of birds in Pisonia 57 Rooting hormone 64 Roseate tern 42, 161 Rosewood 43, 67 Rosewood, seeds 17 Rothmannia annae 17, 67 Rough hermit crab 91 Round Island 139 Roundhead sedge 51 Rubble banks 37-38 Ruddy turnstone 164 Ruspolia differens 104 Sac spiders 99 Sadde 50 Saint-Anne Island 141 Salinity, of sea 35 Salt spray, effects of 47 Salt water crocodile 6 Sand movements 30-34 Sandpipers 164 Sandstone 28-29 Sandstone reef 41 Sargassum 35, 37, 38, 40 Sargassum driftline 41 Sargocentron seychellense 124 Sargocentron spiniferum 123 Scaevola serica 43, 50-51 Scarus rubroviolaceus 126 Schizomida 98 Schizomids 98 Scolopendra subspinipes 101 Scott's termite 106
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Sea birds, and sea conditions 35 Sea characteristics 35-42 Sea cucumbers 86-87 Sea hibiscus 43, 50 Sea level rise 31 Sea level, in past 27 Sea levels, pre-historic 3 Sea shell fossils 29-30 Sea shell trade 18 Sea snails 80-82 Sea snake 145-146 Sea temperatures 23, 35, 75 Sea urchins 88-89 Seabed characteristics 36-39 Seasons, on Cousine 21-24 Secondary herblands/woodlands 51 Secretive flattie 99 Sedge beetle 109 Sedge, and beetle 109 Sedges 51 Seed dispersal, by sea 17 Seed dispersal, by tortoises 19 Seedlings 64, 65 Seeds, on drift line 17 Selenops secretus 99 Semicircular angelfish 122 Senna occidentalis 53 Seradix 64 Sergeants 126 Serpent's head cowrie 80 Sesbania 53 Sesbania sericea 53 Sessile alternanthera 54 Sewage 15 Seychelleptus seychellarum 100-101 Seychelles anemone fish 79 Seychelles archipelago 5-6 Seychelles bank 6 Seychelles cottony cushion scale 107, 114 Seychelles enteropogon 43, 44, 48, 49, 51 Seychelles fody 172-173 Seychelles fody, and seed dispersal 64 Seychelles fruit bat 63, 177 Seychelles giant millipede 100-101 Seychelles giant millipede, crab attack on 93 Seychelles magpie robin 19, 57, 69, 166-169 Seychelles magpie robin, and cockroaches 105 Seychelles magpie robin, predation on skinks 142 Seychelles phyllanthus 47, 53 Seychelles skimmer 103 Seychelles skink 142-143 Seychelles skink, and seed dispersal 64 Seychelles skinks, and mites 99 Seychelles soldierfish 124 Seychelles sunbird 172 Seychelles turtle dove 165-166 Seychelles warbler 19, 169-170
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Seychelles whip scorpion 98 Seychelles white-eye 17-19, 114, 170-171 Seychelles wolf snake 145 Seychelles wood wasp 113 Seychelles, human settlement 6 Seychellois 15, 20 Shade cloth 65 Shallow water 41-42 Sharks 118-119 Sharksucker 121 Sharp-clawed hermit crab 91 Shearwater, early harvesting of 11-12 Shearwaters 147-148 Shearwaters, poaching of 13 Shiny black ladybird 109 Shipworm 83 Shoreline 35 Short-eyed xanthid 96 Short-fruit phyllanthus 45 Short-hand hermit crab 92 Short-spike lepturus 51 Shrimps 85, 86 Shrublands 50-53 Siderea grisea 119 Siganus argenteus 121 Siganus corallinus 121 Siganus rivulatus 121 Siganus spp. 126 Siganus stellatus 121 Silhouette Island 43, 63, 100, 141 Siphonaria sp. 81 Sisal 15 Sixfeeler threadfin 120 Skink 'collars' 143-144 Skinks 142-145 Skunk anemone fish 79 Slat spray 65 Slate pencil urchin 88 Slipper flower 15 Sloping-face termite 106 Small hermit crab 42 Small leaf fig 53, 54, 60 Small-spotted pompano 126 Smeringopus pallidus 99 Snails, land 97 Snails, sea 80-82 Snake, poisnous 127 Snakes 145-146 Snapper swimming crab 94, 95 Snappers 125 Snapping shrimps 86 Snowflake moray 119 Soft brown scale 114 Soft coral, after bleaching event 38 Soil 28-29 Soil profile 29 Soil, health 62
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Soils, and earthworms 97 Solanum americanum 54 Soldierfishes 123-124 Sooty mould 107, 115 Sooty tern 160-161 Sooty tern and restoration 160-161 Sooty tern, and ticks 99-100 Sooty tern, egg harvesting 11 Sophoro tomentosa 17 Soussop 45 South ridge 63 Souvenirs 18 Spangled emperor 124 Spanish dancer 82 Sphryna mokkaran 119 Sphyraena genie 120 Spider conch 80 Spider cricket 105 Spiders 98-99 Spikeweed 33, 47, 46, 48, 49, 60, 63, 68-70 Spiky sedge 51 Spinner dolphin 178 Spiral shell 97 Spitting spiders 99 Spondylus sp. 82 Sponges 75 Sporobolus virginieus 43, 44, 48, 49 Spotted auger 81 Spotted eagle ray 119 Spotted unicornfish 121 Spring tides 31 Squids 83 St Anne Island 178 St Joseph Island 139 Stachytarpheta jamaicensis 47, 52 Staghorn corals 36-37 Star grass 45, 51 Stareye parrotfish 126 Starfish 87-88 Star-legged spiders 99 Starry triggerfish 123 Stellate rabbitfish 121 Stenella longirostris 178 Steno grassland 47 Stenotaphrum dimidiatum 45, 46, 47 Stenotaphrum micranthum 43 Stercorarius parasiticus 161 Sterna anaethetus 160 Sterna bengalensis 161 Sterna bergii 161 Sterna dougalli 161 Sterna fuscuta 160-161 Sterna hirundo 161 Stichodactyla mertensi 79 Stichopus chloronotus 87 Sticky fruits, of Pisonia 58-59 Stinkweed 53
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Stone centipedes 101 Stonefish 125 Storm's rock crab 93 Strawleg coral crab 96 Streptopelia picturata 165-166 Striped periwinkle 82 Striped prawn 42, 86 Stripe-headed millipede 101 Stripeless day gecko 139 Substrates, for corals 37 Subulina octona 97 Sufflamen fraenatus 123 Sulphur damsel 121 Sunbird 171 Surf zone 40 Surge wrasse 126 Surgeonfishes 121, 126 Suriana 64 Suriana maritima 64 Sustainable resource fluxes 62 Swamp area 54 Swamp fern 44 Swamp grass 17, 54 Symphyllia recta 78 Synanceia verrucosa 125 Tabanid flies 110 Taenivra lymna 119 Takamaka 55, 66-67 Takamaka, seeds 17 Tan rock crab 93 Tan rock crab, feeding on millipede 100 Tapinoma melanocephalum 117 Technomyrmex albipes 117 Temminck's stint 164 Tenrec 178 Tenrec ecaudatus 178 Tent cone 81, 90 Terapon jarbua 42 Terebra maculata 81 Terminalia beetle 109 Terminalia catappa 54, 66-67 Terminalia, shading effect 17 Termites 106 Tetraclita sp. 84 Thais shell 91 Thalamita sp. 95 Thalassoma hebraicum 126 Thalassoma purpureum 126 Thespesia populinea 43, 67 Tholymis tillarga 102 Thorn oyster 82 Thornback cowfish 123 Threats, to small islands 1 Three-spot angelfish 122 Ticks 99-100 Tidal range 35 Tiger cowrie 80
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Tiger shark 118 Toads 127 Tobacco 12 Tok-Tok 172-173 Tomato crab 96 Toothed barnacle 84-85 Topography, of Cousine 25-26, 62 Topsoil 28-29 Tortoise genetics 135 Tortoise grazing, and grasshoppers 104 Tortoise grazing, benefitting butterflies 111-112 Tortoise mating 138 Tortoise ponds 137 Tortoise ponds, and dragonflies 102-103 Tortoise, Giant Aldabran 19 Tortoise, grazing by 51 Tortoises 135-138 Tortoises, and impact on seedlings 66 Tortoises, and seed dispersal 64, 136, 139 Tortoises, and seed dispersal 64 Tortoises, maintaining open habitat 97 Trachinotus bailloni 126 Trade winds 22-24, 65 Trades, and sand 30-34 Trades, and sea temperatures 35 Trajectories, ecological 62 Tramea limbata 103 Transparent house ant 117 Tree density 54 Tree heliotrope 64 Tree pipit 174 Tree planting 65 Trevallies 120 Triaenodon obesus 119 Triage 1 Tridacna maxima 82 Tridacna squamosa 82 Triggerfishes 123 Tripletail wrasse 123, 126 Tripneustes cf ventricosus 88 Triton 18 Triumfetta rhomboidea 53 Tropic bird, with Pisonia seeds 59 Tropical earthworm 97 Tropical half-beak 42 Tropicbirds 148-151 True crabs 92-96 Tsunami of 2004 22 Tubipora musica 75-76 Tuna 120 Tunnels, of termites Turbo shell 91-92 Turnera angustifolia 52 Turtle breeding 127-134 Turtle dove 165-166 Turtle eggs 130-131
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Turtle eggs, crab attack on 94 Turtle hatchlings 128-129 Turtle monitoring 19 Turtle nesting 23, 130-134 Turtle nesting season 32 Turtle predation 131 Turtle tabanid 110 Turtle tracks 127, 129 Turtle weights 128-130 Turtles 127-134 Turtles, and beach instability 23 Turtles, harvesting 12 Turtles, shark attack on 118 Tusiops truncates 178 Twig dieback 114-115 Twinspot snapper 125 Twister 102 Tylosurus crocodilus 119 Tyto alba 174 Understorey plants 54, 55, 56, 57, 60 Unicolour honey bee 113-114 Urogymnus asperrimus 119 Vagrant emperor 102 Vagrants, birds 174 Vanessa cardui 111 Variable sea cucumber 86-87 Variegated night moth 112 Vascum shell 91 Vegetables 45 Vegetation classes 72 Vegetation remnants 63 Vegetation succession 69 Vegetation, of Cousine 43-61 Venomous spiders 99 Vernonia 45 Vertebrates, removal of aliens 62 Vespid wasps 112-113 Villas 20 Visiting scientists 64 Volcano barnacle 84 Volunteer activities 64 Wagtails 174 Warbler 169-170 Wasps 112-113 Waterspouts 23 Waves 35 Wedge picassofish 123 Wedge-tailed shearwater 147-148 Well, (water) 11 Whale shark 118 Whales 178 Whimbrel 164 Whip scorpion 98 White hernandia 64, 67 White tern 155-160 White tern predation 158
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White tern, trapped by Pisonia seeds 59 White wagtail 174 White-banded coral crab 96 White-eye 17-19, 114, 170-171 White-flecked decorator crab 96 Whitehead sedge 44, 54 White-spot grouper 125 White-spotted coral crab 96 White-tailed tropicbird 148-151 Wild bean 53, 57 Wild granadilla 46, 66 Wildlife guides 5 Windblow, of trees 55 Withius piger 98 Wolf snake 145 Wolf spiders 99 Woodlands 53-54 Woodlice 117 Worms, marine 84 Wrasses 123, 126 Wright's gardenia 17, 67 Wright's skink 144-145 Wright's skink, and mites 99 Wright's skink, and seed dispersal 64 Xeniid soft coral 38 Ximenia americana 53 Xylocopa caffra 113 Yam 54 Yellow alder 52 Yellow decorator crab 96 Yellow necklacepod 17 Yellow wagtail 174 Yellow wasp 112 Yellow-banded antlion 108 Yellow-banded hermit crab 90-91 Yellow-bellied sea snake 145-146 Yellow-dotted trevally 120 Yellowfin surgeonfish 121, 126 Yellowsaddle goatfish 123 Yellowstripe goatfish 123 Yellowtail wrasse 123 Zanclus cornutus 121 Zanzibar grasshopper 104 Zebrasoma desjardinii 121 Zizeeria knysna 111 Zoanthids 79 Zoanthus sp. Zosterops modestus 170-171 Zosymus aeneus 95-96
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